Fruit structure and systematics of Monimiaceae ss - Red de Bibliotecas

Blackwell Publishing LtdOxford, UKBOJBotanical Journal of the Linnean Society0024-4074(c) 2007 The Linnean Society of London? 2007 

153•• 

265285 

Original Article 

FRUIT STRUCTURE OF MONIMIACEAE 

M. S. ROMANOV 

Et al 

. 

Botanical Journal of the Linnean Society, 2007, 153, 265–285. With 53 figures 

Fruit structure and systematics of Monimiaceae s.s. 

(Laurales) 

MIKHAIL S. ROMANOV 1 *, PETER K. ENDRESS 2 , ALEXEY V. F. CH. BOBROV 3 , 

ALEXANDER P. MELIKIAN 4 and ALEJANDRO PALMAROLA BEJERANO 5 

1 N. V. Tzitzin Main Botanic Garden of the Russian Academy of Sciences, 127276, Botanical St., 4, Moscow, 

Russian Federation 

2 Institute of Systematic Botany and Botanic Garden, University of Zurich, Zollikerstrasse 107, CH-8008, 

Zurich, Switzerland 

3 Recent Deposits and Pleistocene Palaeogeography Department, Geographical Faculty, and 

4 Department of Higher Plants, Biological Faculty, M. V. Lomonosov Moscow State University, 119992, 

Moscow, Russian Federation 

5 Jardín Botánico Nacional, Universidad de la Habana, Carretera ‘El Rocio’, Km 3 1/2, Calabazar, 

Boyeros, C. P. 19230, Ciudad de la Habana, República de Cuba 

Received March 2006; accepted for publication September 2006 

Fruit structure (anatomy) was studied in 27 species of 15 genera of Monimiaceae s.s. Almost all have apocarpous 

gynoecia, with the carpels more or less surrounded by a floral cup. The fruitlets are presented on the opened floral 

cup, which, depending on its pre- and post-floral development, differentially contributes to the attractive part of the 

mature fruit. Morphologically similar fruits may differ conspicuously in anatomical structure. Based on anatomical 

characters two different fruit forms were found: drupe(let)s (with compact sclerenchymatic endocarp forming a stone: 

putamen) and berry(let)s (with parenchymatic endocarp, and mesocarp parenchyma containing isolated sclereid 

nests). Four types of drupelets differing by the endocarp structure were tentatively distinguished: (1) the Monimiatype 

has a many-cell-layered putamen of large isodiametric sclereids, interrupted on the ventral side by few radial 

rows of small sclereids; (2) the Hortonia-type has a few-cell-layered putamen of isodiametric, especially thick-walled 

sclereids – it may be composed of two lateral halves, i.e. with the sclerenchyma partially interrupted on the ventral 

and dorsal sides (but without rows of small sclereids); (3) the Mollinedia-type has a few-cell-layered putamen, with 

more or less radially elongate sclereids with wavy cell walls; and (4) the Hedycarya-type has a one-cell-layered putamen 

of pronouncedly radially elongate sclereids with wavy cell walls. Drupelets of some taxa with a single-celllayered 

endocarp with only weakly thickened cell walls may represent a transition from drupelets to berrylets. The 

fruit structure supports three major clades recognized earlier by morphological studies and by molecular phylogenetic 

analyses: (1) Monimioideae (Monimia-type drupelets), (2) Hortonieae of Mollinedioideae (Hortonia-type 

drupelets), and (3) the remainder of Mollinedioideae (Hedycarya- and Mollinedia-types) and berrylets. Fruit 

structure also supports the close relationship of Monimiaceae and Lauraceae. © 2007 The Linnean Society of 

London, Botanical Journal of the Linnean Society, 2007, 153, 265–285. 

ADDITIONAL KEYWORDS: berry(let) – comparative carpology – drupe(let) – fruit evolution – pericarp 

anatomy – phylogeny – putamen. 

INTRODUCTION 

*Corresponding author. E-mail: mikhailsrom@mail.ru 

The family Monimiaceae s.s. (exclusive of Atherospermataceae 

and Siparunaceae) is well supported as a 

clade in recent molecular studies, and as part of Laurales 

(Renner, 1998, 1999; Renner & Chanderbali, 

2000; APG, 2003; Hilu et al., 2003). Earlier, Amborellaceae 

and Trimeniaceae, and sometimes Chloranthaceae, 

were also included in Monimiaceae s.l. or as 

separate families in Laurales (Perkins, 1925; Money, 

Bailey & Swamy, 1950; Cronquist, 1981; Takhtajan, 

1987, 1997; Thorne, 1992; but not Thorne 2000). How- 

© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153, 265–285 265

266 M. S. ROMANOV ET AL. 

ever, Amborellaceae and Trimeniaceae were found to 

be among the basalmost angiosperms and Chloranthaceae 

to be isolated and difficult to place, and thus 

all three families had to be excluded not only from 

Monimiaceae but also from Laurales (e.g. Mathews & 

Donoghue, 1999; Qiu et al., 1999, 2005; Soltis, Soltis & 

Chase, 1999; APG, 2003). The isolated position of 

Amborellaceae is also supported by floral and carpological 

features (Endress & Igersheim, 2000; Bobrov 

et al., 2005). In molecular phylogenetic studies Monimia, 

Palmeria and Peumus form a clade, which is sister 

to the other Monimiaceae s.s. (Renner, 1998, 1999, 

2002; Renner & Chanderbali, 2000). The distinctness 

of this group was also recognized by morphologists 

(Philipson, 1993; Takhtajan, 1997); this clade is now 

treated as subfamily Monimioideae (Philipson, 1987), 

and the other members of the family as Mollinedioideae. 

Within Mollinedioideae, Hortonia is sister to 

the other genera (Renner, 1998, 1999, 2002; Renner & 

Chanderbali, 2000). The Madagascan Decarydendron 

and Tambourissa form a (weakly supported) clade, 

which is sister to all other remaining genera (Renner, 

2002). The bulk of the genera, comprising the South 

American and most Australasian groups, form a 

moderately supported clade (not including Xymalos, 

Hedycarya, Levieria or Kibaropsis) (Renner, 2002). 

The relationships of some of these groups are still 

unresolved, and there is no agreement also from a 

structural point of view (Endress, 1980b; Philipson, 

1993; Bobrov et al., 2003b). 

The representatives of Monimiaceae s.s. are characterized 

by apocarpous gynoecia with uniovulate carpels 

(Endress & Igersheim, 1997). The carpels are 

borne in a more or less flat or concave floral cup (Perkins 

& Gilg, 1901; Perkins, 1925; Endress, 1980a, b; 

Endress & Lorence, 1983; Lorence, 1985; Philipson, 

1986, 1993; Romanov & Bobrov, 2002). Tambourissa 

species have inferior ovaries congenitally fused with 

the floral cup, which results in a kind of syncarpous 

gynoecium (Endress, 1979, 1980b; Endress & Lorence, 

1983; Lorence, 1985). The upper part of the floral cup 

either abscises from the base just after anthesis 

(rarely the cup is small from the beginning without 

abscission necessary), or it encloses the developing 

fruitlets and grows with them up to maturity and then 

splits open with irregular valves (Endress, 1980b; 

Lorence, 1985). In the first case, the unabscised base 

of the floral cup expands only as much as to accommodate 

the growing fruitlets and is commonly inconspicuous 

at fruit maturity (e.g. Steganthera and Wilkiea 

species), or expands slightly more (Levieria), or the stipes 

of the druplelets slightly enlarge (Steganthera, 

Mollinedia), providing some colour contrast (see figures 

in Renner & Hausner, 1997; Cooper & Cooper, 

2004). In the second case, the entire floral cup takes 

considerable part in the presentation of the fruitlets 

by contrasting colours (e.g. Hennecartia, Monimia, 

Palmeria and Tambourissa species) (Perkins & Gilg, 

1901; Money et al., 1950; Endress, 1980b; Lorence, 

1985; Philipson, 1986, 1993). As the outer part of the 

pericarp of the fruitlets of many Monimiaceae s.s. 

appears to be fleshy or pulpy and the inner zone hard, 

the fruitlets of the representatives of the family have 

usually been referred to as drupe(let)s (Baillon, 1867– 

69; Perkins & Gilg, 1901; Money et al., 1950; Takhtajan, 

1966, 1997; Corner, 1976; Cronquist, 1981; 

Lorence, 1985; Philipson, 1986, 1993). However, that 

such superficially similar fruitlets may be internally 

different has been shown by the genus Amborella, 

which was found to be unrelated to Monimiaceae but 

sister to all other extant angiosperms (e.g. Qiu et al., 

1999), and in which the seeming druplets have a hard 

part that is mainly derived from the mesocarp, 

whereas the endocarp is thin (Bobrov et al., 2005). 

This result in Amborella prompted us to undertake a 

comparative anatomical study on the fruit structure in 

a broad array of Monimiaceae s.s. in order to elucidate 

the diversity and to pursue further the systematic significance 

of the fruits in basal angiosperms. 

MATERIAL AND METHODS 

Part of the studied material (Table 1) was dry, part 

was fixed in FAA and stored in ethanol (70%). Dry 

fruitlets were treated in Strasburger solution (glycerin/ethanol); 

they were embedded in paraffin, and 

transverse (TS) and longitudinal sections (LS) at 10– 

20 µm were made with a slide microtome. The sections 

were stained with phloroglucinol and hydrochloric 

acid to study details of lignification of cell walls in different 

topographical zones of the pericarp, and were 

preserved in glycerin. Standard morphological and 

anatomical procedures were used (Bondartzev, 1954; 

Prozina, 1960; O’Brien & McCully, 1981). The liquidfixed 

fruitlets were embedded in Kulzer’s Technovit 

7100 [2-hydroxyethyl methacrylate (HEMA)], sectioned 

at 10 µm with a rotary microtome (Microm HM 

355), stained with ruthenium red and toluidine blue, 

and enclosed in Histomount (following Weber & Igersheim, 

1994). The microtome sections were studied 

with light microscopy. Fruitlet structure was also 

examined with scanning electron microscopy (‘HITA- 

CHI’ S-405-A and Camscan S-2), after critical-point 

drying and sputter-coating with gold–palladium. 

RESULTS 

All genera of Monimiaceae s.s. (except Tambourissa) 

have free carpels that develop into free fruitlets. In 

these the pericarp is differentiated into three histogenetic 

zones (exocarp, mesocarp and endocarp) and into 

three or more histological zones. 

© 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153, 265–285

FRUIT STRUCTURE OF MONIMIACEAE 267 

Table 1. Investigated species and specimens 

Hedycarya angustifolia A.Cunn., mature fruits (liquid-fixed), P.K. Endress, # 5033, Australia 1980 (Z) 

Hedycarya arborea J.R.Forst. & G.Forst., mature fruits (liquid-fixed), P.K. Endress, # 6390, New Zealand 1981 (Z) 

Hedycarya cf. chrysophylla Perkins, mature fruits (liquid-fixed), P.K. Endress, # 6322, New Caledonia 1981 (Z) 

Hedycarya crassifolia Gillespie, mature fruits (dry), A.C. Smith, # 5149, Fiji 1947 (LE) 

Hedycarya cupulata Baill., mature fruits (dry), G. McPherson, # 1783, New Caledonia 1979 (LE) 

Hedycarya dentata G.Forst., mature fruits (dry), M. Hombron, s.n., New Zealand 1841 (LE) 

Hedycarya dorstenioides A.Gray, mature fruits (dry), A.C. Smith, # 6954, Viti Levu 1947 (LE) 

Hedycarya parvifolia Perkins & Schltr., mature fruits (dry), G. McPherson, # 1621, New Caledonia 1979 (LE) 

Hennecartia omphalandra Poiss., mature fruits (dry), J.E. Montes, # 9515, Brazil 1950 (LE) 

Hortonia floribunda Wight ex Arn., mature fruits (dry), R. Wight, # 2491, Sri Lanka 1836 (LE) 

Hortonia ovalifolia Wight, mature fruits (dry), L. Bernardi, # 15947, Sri Lanka 1975 (LE) 

Kibara coriacea Hook.f. & Thomson, mature fruits (dry), M. Ramos, # 4317, Philippines 1923 (LE) 

Kibaropsis caledonica (Guillaumin) Jérémie, mature fruits (liquid-fixed), P.K. Endress, # 6311, New Caledonia 1981 (Z) 

Levieria nitens Perkins, mature fruits (dry), H.O. Forbes, # 702, New Guinea 1885–86 (LE) 

Matthaea pubescens Merr. ex Perkins, mature fruits (dry), A.D.E. Elmer, # 10699, Philippines 1909 (LE) 

Mollinedia elliptica A.DC., mature fruits (dry), L. Riedel & B. Luschnath, # 312, Brazil 1832 (LE) 

Mollinedia stenophylla Perkins, mature fruits (dry), L. Riedel & B. Luschnath, # 315, Brazil 1832 (LE) 

Monimia rotundifolia Thouars, mature fruits (dry), L. Boivin, # 1120, La Réunion, s.d. (LE) 

Peumus boldus Molina, mature fruits (dry), O. Zalensky, # 15, Chile 1968 (LE) 

Palmeria scandens F.Muell., mature fruits (dry), P. Melville, # 3613, Queensland, Australia 1953 (LE) 

Steganthera ilicifolia A.C.Sm., mature fruits (liquid-fixed), P.K. Endress, # 4074, Papua New Guinea 1977 (Z) 

Steganthera fengeriana Perkins, mature fruits (dry), T.G. Hartley, # 9967, New Guinea 1962 (LE) 

Steganthera salomonensis Philipson, mature fruits (dry), P.F. Hunt, # 2415, Solomon Islands, s.d. (LE) 

Tambourissa comorensis Lorence, mature fruits (dry), L. Bernardi, # 11803, Comores 1967 (LE) 

Tambourissa tau Lorence, mature fruits (liquid-fixed), D.H. Lorence, # 2950, Mauritius 1979 (Z) 

Tetrasynandra laxiflora Perkins, mature fruits (dry), M.S. Clemens, s.n., Queensland, Australia 1947 (LE) 

Wilkiea wardellii (F.Muell.) Perkins, mature fruits (dry), F. von Mueller, s.n., Queensland, Australia, s.d. (LE) 

MONIMIA ROTUNDIFOLIA 

The several (5–10) carpels develop into few drupelets. 

They remain enclosed by the floral cup. Only at maturity 

does the floral cup dehisce into 3–5 irregular 

valves and the irregularly flattened drupelets are 

exposed (Lorence, 1985) (Fig. 50). The inner surface of 

the floral cup forms a colour contrast with the drupelets 

(red vs. orange in Monimia ovalifolia; D. H. 

Lorence, pers. comm.). 

The pericarp is differentiated into four distinct histological 

zones (Fig. 5). The first zone (the exocarp) 

consists of the one-cell-layered epidermis of small, 

flattened, ellipsoidal tanniferous cells, and with a thin 

cuticle. The second and third zones are formed by the 

mesocarp. The second zone consists of 3–8 layers of 

thin-walled parenchymatic cells, interspersed with 

numerous large, spherical–ellipsoidal, thin-walled 

resiniferous cells. The vascular system is situated in 

the inner area of the second zone, with the vascular 

bundles situated above the ribs of the endocarp. The 

third zone consists of 1–5 layers of small, flattened, 

tangentially elongate cells with unevenly insignificantly 

thickened cell walls, the zone of hydrocytes. The 

fourth zone (the endocarp), making up about threequarters 

of the pericarp thickness, is composed of 13– 

21 layers of large, isodiametric sclereids with thickened, 

lignified, striate, canaliculate, broadly wavy cell 

walls (Fig. 29). The innermost layers of the endocarp 

are formed by insignificantly tangentially orientated 

sclereids. In the ventral median plane of the endocarp 

there are two radial rows of smaller sclereids with 

somewhat less thickened walls, which appear to result 

in a fainter area of the putamen (Figs 28, 50). The 

periphery of the endocarp is irregularly zigzag-shaped 

in TS and LS. The cuticle of the inner epidermis is 

inconspicuous. 

PALMERIA SCANDENS 

The several carpels develop into (few) drupelets. They 

remain enclosed by the floral cup. Only at maturity 

does the floral cup dehisce into several irregular 

valves and the irregularly flattened drupelets are 

exposed. The red inner surface of the floral cup displays 

a colour contrast with the black drupelets (Cooper 

& Cooper, 2004; P.K.E., pers. observ.). The fruits of 

P. gracilis are similar (Fig. 1). 

The pericarp is differentiated into five distinct histological 

zones (Figs 6, 30). The first zone (the exocarp) 

is formed by the one-cell-layered epidermis of 

ellipsoidally rectangular cells with evenly thickened 

cell walls, the cell walls dark by tannins, and with a 



Figures 1–4. Mature fruits. Fig. 1. Palmeria gracilis Perkins. Fig. 2. Tambourissa castri-delphinii Cavaco (courtesy W. 

Barthlott). Fig. 3. Hedycarya arborea. Fig. 4. Wilkiea huegeliana A.DC. 

thick, even cuticle. The second, third and fourth zones 

are formed by the mesocarp. The second zone consists 

of 1–2 layers of large, spherical or ellipsoidal, thinwalled 

resiniferous cells. The third zone is formed by 

5–6 layers of large, spherical, thin-walled ethereal oil 

cells, interspersed with few small, thin-walled cells. 

The vascular system is situated in the third zone. The 

fourth zone is represented by 1–2 layers of small, 

ellipsoidal–angular hydrocytes with unevenly thickened 

cell walls. The fifth zone (the endocarp), representing 

up to three-quarters of the pericarp thickness, 

is formed by 40–55 layers of isodiametric sclereids 

with heavily thickened, lignified, striate, canaliculate, 

somewhat wavy cell walls (Fig. 31). In the ventral 

median plane of the endocarp there are 2(−5) radial 

rows of radially elongate, thick-walled sclereids, 

which appear to result in a fainter area of the 

putamen. The cuticle of the inner epidermis is 


PEUMUS BOLDUS 

The 3–5 carpels develop into 2–5 drupelets (Perkins, 

1925). The upper part of the floral cup abscises with a 

ring-shaped abscission zone (Martínez-Laborde, 1983; 

Philipson, 1993). However, it is not clear whether this 

takes place in the ripe fruit or earlier. At maturity the 

drupelets are exposed on the inner side of the remaining 

part of the floral cup. 

The pericarp is differentiated into three histological 

zones (Figs 7, 32). The first zone (the exocarp) is represented 

by a one-cell-layered epidermis of tangentially 

elongate, rectangular tanniferous cells with 

unevenly thickened cell walls and with a thick, even 

cuticle. The second zone (the mesocarp) consists of 15– 

25 layers of irregularly ellipsoidal, thin-walled tanniferous 

cells, interspersed with large, spherical–ellipsoidal, 

thin-walled etheral oil cells. The vascular system 

is situated in the middle part of the mesocarp. The 

third zone (the endocarp), representing up to fourfifths 

of the pericarp thickness, consists of 15–25 layers 

of isodiametric sclereids with heavily thickened, 

lignified, striate, canaliculate, somewhat wavy cell 

walls (Fig. 33). In the ventral median plane of the 

endocarp the putamen is interrupted by an area of few 

(2–3) radial rows of smaller-celled sclereids (Fig. 32). 

The cuticle of the inner epidermis is thin and 




Figures 5–10. Schematic TS of pericarp of mature fruitlets (En = endocarp; Ex = exocarp; Fc = floral cup; M = mesocarp; 

dark grey = resin cells; light grey = ethereal oil cells; hatched = hydrocytes; black = tanniferous cells, also cells with tannins 

in cell walls). Fig. 5. Monimia rotundifolia. Fig. 6. Palmeria scandens. Fig. 7. Peumus boldus. Fig. 8. Hortonia floribunda. 

Fig. 9. Tambourissa comorensis. Fig. 10. Kibaropsis caledonica. Scale bars: Figs 5–9 = 0.1 mm; Fig. 10 = 0.05 mm. 



Figures 11–16. Schematic TS of pericarp of mature fruitlets (En = endocarp; Ex = exocarp; M = mesocarp; dark 

grey = resin cells; light grey = ethereal oil cells; hatched = hydrocytes; black = tanniferous cells, also cells with tannins in 

cell walls). Fig. 11. Levieria nitens. Fig. 12. Hedycarya cupulata, Fig. 13. Hedycarya dorrstenioides. Fig. 14. Mollinedia 

elliptica. Fig. 15. Mollinedia stenophylla. Fig. 16. Hennecartia omphalandra. Scale bars: Figs 11, 12, 14, 15 = 0.05 mm; 

Fig. 13 = 0.1 mm; Fig. 15 = 0.03 mm. 



Figures 17–21. Schematic TS of pericarp of mature fruitlets (En = endocarp; Ex = exocarp; M = mesocarp; dark 

grey = resin cells; light grey = ethereal oil cells; hatched = hydrocytes; black = tanniferous cells, also cells with tannins in 

cell walls). Fig. 17. Wilkiea wardellii. Fig. 18. Kibara coriacea. Fig. 19. Steganthera salomonensis. Fig. 20. Tetrasynandra 

laxiflora. Fig. 21. Matthaea pubescens. Scale bars: Fig. 17 = 0.05 mm; Figs 18–21 = 0.1 mm. 



Figures 22–27. Microtome TS of pericarp of mature or submature fruitlets (fruit in Fig. 27) (stained with ruthenium red 

and toluidine blue) (En = endocarp; Ex = exocarp; M = mesocarp; Sc = seed coat). Fig. 22. Tambourissa tau Lorence. Fig. 23. 

Kibaropsis caledonica Jérémie. Fig. 24. Hedycarya angustifolia A. Cunn. Fig. 25. Hedycarya arborea. Fig. 26. Steganthera 

ilicifolia A.C. Sm. Fig. 27. Laurus nobilis L. (Lauraceae). Scale bars: Figs 22, 24–27 = 0.2 mm; Fig. 23 = 0.1 mm. 



Figures 28–33. SEM micrographs of TS (LS in Fig. 28) of pericarp (En = endocarp; Eoc = ethereal oil cell; Ex = exocarp; 

M = mesocarp). Figs 28, 29. Monimia rotundifolia. Fig. 28. LS, endocarp with partly torn weaker area of small sclereids 

(arrow) in apical part, corresponding to the area with smaller sclereids on the ventral side. Fig. 29. Endocarp. Figs 30, 31. 

Palmeria scandens. Fig. 30. Lateral side, pericarp. Fig. 31. Endocarp. Figs 32, 33. Peumus boldus. Fig. 32. Ventral side, 

endocarp with radial area of small sclereids (narrow arrow); broad arrows point to vascular bundles. Fig. 33. Close-up of 

outer part of pericarp. Scale bars: Figs 28, 30, 32 = 0.3 mm; Figs 29, 31, 33 = 0.03 mm. 



HORTONIA FLORIBUNDA 

The several carpels develop into few fruitlets. At 

maturity the shortly stipitate drupelets are presented 

on the small, reflexed floral cup. The fruitlet outline is 

elliptic in TS (smaller in lateral direction than in 

median direction) (Fig. 51). 


zones (Figs 8, 34, 35). The first zone (the exocarp) 

consists of the one-cell-layered epidermis of 

large roundish–rectangular cells, with evenly thickened 

walls, the walls dark by tannins and with a thick 

uneven cuticle. The second and third zones are formed 

by the mesocarp. The second zone consists of 20–28 

layers of thin-walled, irregularly ellipsoidal, somewhat 

tangentially elongate cells, interspersed with 

numerous large spherical–ellipsoidal, thin-walled 

resiniferous cells; there are also some large resiniferous 

sclereids with thickened, lignified cell walls. Tanniferous 

cells are present in the outer 3–8 cell layers, 

and also cells with tannins in the cell walls. The vascular 

system is situated in the middle area of the second 

zone. The third zone comprises 2–6 layers of 

angular–ellipsoidal, tangentially elongate hydrocytes 

with reticulate cell-wall thickening. The fourth zone 

(the endocarp) consists of 3–6 layers of large, roundish–multiangular 

resiniferous sclereids of unequal 

size, with exceedingly thickened, lignified, striate, 

canaliculate cell walls. The endocarp (putamen) is protruding 

ventrally and dorsally in the median plane 

forming two ridges. The inner morphological surface is 

similarly protruding but appears not to reach the 

periphery of the endocarp, which results in two 

’valves’ (Figs 34, 35, 51). The cuticle of the inner epidermis 

is thin and even. 

Hortonia ovalifolia differs by the presence of more 

numerous resiniferous sclereids in the second zone, 

only 1–2 layers of hydrocytes forming the third zone, 

lesser thickening of the sclereid cell walls in the 

endocarp, and lack of ventral and dorsal ridges in the 

endocarp. 

TAMBOURISSA COMORENSIS 

The fruit in Tambourissa is unusual because the ovaries 

are inferior, immersed in the floral cup, which 

results in an unusual kind of syncarpous fruit 

(Endress, 1980b; Endress & Lorence, 1983; Lorence, 

1985). Therefore, an exocarp that surrounds each individual 

’fruitlet’ is not present (Fig. 36). However, each 

carpel differentiates histological structures that functionally 

correspond to a pericarp, which then separates 

from the tissue of the floral cup or neighbouring 

carpels. Commonly in the genus the ’fruitlets’ are 

orange or red, surrounded by yellow or orange parts of 

the floral cup (Lorence, 1985) (Fig. 2). 

The fruit wall is differentiated into five histological 

zones of which the third and fourth are similar to a 

mesocarp and the fifth to an endocarp (Fig. 9). The 

first zone, the outer epidermis, is part of the united 

complex of carpels and floral cup. The second zone is 

formed by up to 100 layers of isodiametric thin-walled 

cells interspersed with numerous spherical thinwalled 

ethereal oil cells and scattered solitary or 

groups of 2–13 sclereids with thickened, lignified, striate, 

canaliculate cell walls. The sclereids differ from 

each other in their wall thickness. In places the outer 

cell layers of the second zone divide in tangential 

direction and form a periderm composed of up to 

10–15 indistinct cell layers. The third zone consists of 

15–30 layers of small, thin-walled fusiform cells, interspersed 

with numerous large, spherical–ellipsoidal, 

thin-walled resiniferous and ethereal oil cells. The 

vascular system is situated in the third zone. The 

fourth zone is represented by the one-cell-layered 

inner hypodermis, which is composed of tangentially 

elongate, ellipsoidal hydrocytes with unevenly thickened 

cell walls. The fifth zone (the endocarp) consists 

of 2–4(−5) layers of large unequal sclereids, with thickened, 

lignified, striate, canaliculate, pronouncedly 

wavy cell walls (Fig. 37). The cuticle of the inner epidermis 

is inconspicuous. 

Tambourissa tau differs by fewer secretory cells (i.e. 

resiniferous and ethereal oil cells) in the third zone, 

and more pronouncedly tangentially elongate cells 

with thickened and lignified cell walls in the fourth 

zone (Fig. 22). 

KIBAROPSIS CALEDONICA 

The 40–60 carpels develop into several red drupelets, 

which are presented on the reflexed floral cup 

(Jérémie, 1977). The fruitlet outline is circular in TS. 




rather small, rectangular, thin-walled tanniferous 

cells and with a thick, wavy cuticle. The second and 

third zones (the mesocarp) consist of 55–65 cell layers. 

The second zone is represented by 10–12 layers of relatively 

small, thin-walled parenchymatic cells, interspersed 

with small nests of up to c. 20 sclereids with 

thickened, lignified, striate, canaliculate cell walls. 

More than half of the thin-walled cells of this zone are 

tanniferous. The third (and thickest) zone is composed 

of relatively large parenchymatic cells, interspersed 

with numerous scattered spherical–ellipsoidal, thinwalled 

resiniferous cells. In the inner part of this zone 

there are numerous ethereal oil cells and very few solitary 

scattered sclereids with thickened, lignified, striate, 

canaliculate, cell walls. The vascular system is 

situated in the third zone. The fourth zone (the 



endocarp) consists of 7–10 layers of large unequal 

sclereids, with thickened, lignified, striate, canaliculate, 

somewhat wavy cell walls. Some cells are markedly 

radially elongate. The cuticle of the inner 

epidermis is inconspicuous. 

LEVIERIA NITENS 

The numerous carpels develop into numerous sessile 

fruitlets, which are presented at maturity on the 

reflexed floral cup (Philipson, 1980). The fruitlet outline 

is circular in TS. 




angular, somewhat tangentially elongate cells, with 

unevenly thickened cell walls, and with an inconspicuous 

cuticle. The second and third zones are formed by 

the mesocarp. The second zone is composed of 25–39 

layers of small, nearly ellipsoidal, thin-walled parenchymatic 

cells, interspersed with numerous large, 

spherical–ellipsoidal thin-walled resiniferous cells. 

The vascular system is situated in the inner area of 

the second zone. The third zone is irregularly thick, 

comprising 1–4 layers of angular–ellipsoidal, tangentially 

elongate hydrocytes with reticulate cell-wall 

thickening. The fourth zone (the endocarp) consists of 

one layer of large, radially elongated sclereids, with 

heavily thickened, lignified, striate, canaliculate, 

broadly wavy cell walls (Fig. 39). The cuticle of the 

inner epidermis is inconspicuous. 

HEDYCARYA CUPULATA 

The 9–15 carpels develop into few black drupelets, 

which are presented at maturity on the reflexed floral 

cup (Jérémie, 1978). In H. arborea the drupelets are 

orange (Fig. 3). The fruitlet outline is circular in TS 

(Fig. 53). 




large ellipsoidally rectangular cells, with unevenly 

thickened walls, and is covered by a very thick, even 


mesocarp. The second zone is represented by 10–14 

layers of thin-walled, fusiform parenchymatic cells, 

interspersed with numerous large spherical–ellipsoidal, 

thin-walled resiniferous cells. The thin-walled 

fusiform cells are smaller in the peripheral part of 

the second zone. The vascular system is situated in 

the inner area of the second zone. The third zone 

comprises 2–4 layers of nearly rectangular, tangentially 

elongate hydrocytes with reticulate cell-wall 

thickening. The fourth zone (the endocarp) consists of 

one layer of large, radially elongate sclereids, with 

heavily thickened, striate, canaliculate walls. Only 

the primary cell walls are lignified. The cell walls are 

heavily broadly wavy, which may give the wrong 

impression of the endocarp as consisting of several 

cell layers. The cuticle of the inner epidermis is 


Hedycarya parvifolia differs in more numerous cell 

layers of the second and third zones. In H. angustifolia, 

H. cf. chrysophylla and H. dorstenioides the second 

zone is more multilayered, but, by contrast, the third 

zone is thinner and consists of a single layer of crescent-shaped 

hydrocytes (1–2 layers in H. cf. chrysophylla 

and H. crassifolia) (Figs 13, 24, 41). In 

H. angustifolia and H. crassifolia the cells of the 

endocarp are two or more times shorter (in radial 

direction) than in the other studied species. In 

H. arborea and H. dentata only a single zone is differentiated 

in the mesocarp, corresponding to the second 

zone in H. cupulata (i.e. the zone of hydrocytes is 

absent); in the mesocarp scattered nests of 1–5 sclereids 

with thickened, lignified cell walls are developed 

(Fig. 25). 

MOLLINEDIA ELLIPTICA 

The 10–12 carpels develop into few sessile drupelets. 

After anthesis the upper part of the floral cup abscises 

from the lower part so that the fruitlets are not covered 

during development. At maturity they are presented 

on the reflexed floral cup (Perkins & Gilg, 

1901). The fruitlet outline is circular in TS (Fig. 52). 




large rectangular palisade cells, with unevenly thickened 

cell walls and triangular lumens, and with a 

thick, even cuticle. The second, third and fourth zones 

are formed by the mesocarp. The second zone is represented 

by a one-cell-layered hypodermis composed 

of square–rounded cells with insignificantly thickened 

cell walls. The vascular system is situated in the inner 

area of the second zone. The third zone consists of 15– 

25 layers of ellipsoidally flattened, thin-walled cells, 

interspersed with numerous large, spherical–ellipsoidal, 

thin-walled resiniferous cells. Sometimes 1–3 

outer cell layers of the third zone are represented by 

rounded–rectangular, thin-walled cells. The fourth 

zone comprises 1–2 layers of rather large, ellipsoidal, 

tangentially elongate tanniferous hydrocytes. The 

fifth zone (the endocarp) consists of 2–4 layers of large 

unequal sclereids, with thickened, lignified, striate, 

canaliculate, pronouncedly broadly wavy cell walls 

(Fig. 43). The cuticle of the inner epidermis is inconspicuous. 

Mollinedia stenophylla differs in the number of cell 

layers and number of secretory cells (i.e. resiniferous 



Figures 34–39. SEM micrographs of TS of pericarp (En = endocarp; Ex = exocarp; H = hydrocytes; M = mesocarp; 

Rc = resin cells; Sc = seed coat). Figs 34, 35. Hortonia floribunda (narrow arrow points to slit in endocarp; broad arrow 

points to vascular bundle). Fig. 34. Dorsal side. Fig. 35. Ventral side. Figs 36, 37. Tambourissa comorensis. Fig. 36. Part 

of two neighbouring ‘fruitlets’. Fig. 37. Endocarp. Figs 38, 39. Levieria nitens. Fig. 38. Pericarp. Fig. 39. Endocarp. Scale 

bars: Figs 34, 35, 37, 38 = 0.1 mm; Fig. 36 = 0.3 mm; Fig. 39 = 0.03 mm. 



and etheral oil cells) in the mesocarp, and in cell structure 

in the endocarp (Fig. 15). 

HENNECARTIA OMPHALANDRA 

Of the one or two carpels commonly one develops into 

a drupelet (Endress, 1980b). The drupelet(s) remain(s) 

enclosed by the floral cup. Only at maturity does the 

floral cup dehisce into several irregular valves, and 

the black drupelet is presented on the orange cup surface 

(Martínez-Laborde, 1983). The fruitlet outline is 

circular in TS. 

The pericarp is differentiated into three histological 

zones (Fig. 16). The first zone (the exocarp) consists of 

the one-cell-layered epidermis of large, square, tanniferous 

cells with unevenly thickened cell walls, and 

with a very thick, wavy cuticle, and a single-layered 

hypodermis of somewhat crushed rectangular, tanniferous 

cells, which appears to be derived from the epidermis, 

as suggested by radial cell rows. The second 

zone (the mesocarp) comprises 23–30 layers of relatively 

large parenchymatic cells, interspersed with 

numerous large spherical–ellipsoidal, thin-walled 

resiniferous cells. In the peripheral area the thinwalled 

cells are smaller The vascular system is situated 

in the middle part of the second zone. The innermost 

layer of the second zone contains some sclereids 

with thickened, lignified cell walls. The third zone (the 

endocarp) consists of a single layer of large, radially 

elongate sclereids, with heavily thickened, lignified, 

striate, canaliculate cell walls. The primary cell walls 

are lignified more heavily. The cell walls are pronouncedly 

wavy, which may give the wrong impression 

of the endocarp as consisting of several cell layers. The 

cuticle of the inner epidermis is thin. 

WILKIEA WARDELLII 

The several carpels develop into few stipitate drupelets. 

After anthesis the upper part of the floral cup 

abscises from the lower part so that the fruitlets are 

not covered during development. At maturity they are 

presented on the reflexed yellow remnant of the floral 

cup. In W. wardellii the fruitlets are red but otherwise 

in the genus commonly black (Cooper & Cooper, 2004) 

(Fig. 4). The fruitlet outline is circular in TS. 

The pericarp is differentiated into four histological 

zones (Figs 17, 44). The first zone (the exocarp) consists 

of the one-layered epidermis of rectangular tanniferous 

cells and with a moderately developed even 


mesocarp. The second zone is a one-cell-layered irregular 

hypodermis of tanniferous cells, which are rather 

small as compared with the cells of the third zone. The 

third zone consists of 23–28 layers of large, thinwalled 

parenchymatic cells (some of which are tanniferous), 

interspersed with numerous large, spherical, 

thin-walled resiniferous cells. There are numerous solitary 

sclereids or groups of up to three isodiametric 

sclereids with markedly (or rarely insignificantly) 

thickened, lignified, striate, canaliculate cell walls. 

The vascular system is situated in the third zone. The 

fourth zone (the endocarp) is composed of a single 

layer of rectangular sclereids with U-shaped, 

unevenly heavily thickened lignified, striate, canaliculate 

cell walls (Fig. 45). A cuticle is not apparent on 

the inner epidermis. 

KIBARA CORIACEA 

The c. 20 carpels develop into few sessile berrylets. 



during development. At maturity they are black 

and are presented on the yellow to orange reflexed 

remnant of the floral cup (Philipson, 1985, 1986). The 

fruitlet outline is circular in TS. 




ellipsoidal tanniferous cells with unevenly irregularly 

thickened cell walls and with a thick, even cuticle. The 

second, third and fourth zones are formed by the 

mesocarp, consisting of 37–43 cell layers. The second 

zone is represented by 13–15 layers of spherical–ellipsoidal, 

thin-walled cells, some of them resiniferous 

(especially the outermost layer), and some tanniferous. 

The third zone comprises 10–15 layers of multiangular, 

thin-walled cells, interspersed with numerous 

nests of 10–30 sclereids, with heavily thickened, 

striate, lignified, canaliculate cell walls. The fourth 

zone consists of 14–17 layers of somewhat tangentially 

elongate thin-walled cells, interspersed with spherical, 

thin-walled ethereal oil cells and some tanniferous 

cells. The vascular system is situated in the fourth 

zone. The fifth zone (the endocarp) is composed of a 

single layer of medium-sized, somewhat tangentially 

elongate, thin-walled cells. The cuticle of the inner epidermis 


STEGANTHERA SALOMONENSIS 

The numerous carpels develop into several stipitate 

berrylets. After anthesis the upper part of the floral 

cup abscises from the lower part so that the fruitlets 

are not covered during development. At maturity they 

are presented on the reflexed remnant of the floral 

cup. The fruitlet outline is circular in TS. 

The pericarp is differentiated into three distinct histological 


consists of the one-cell-layered epidermis with 

unevenly thickened cell walls, and with a thin cuticle. 



Figures 40–45. SEM micrographs of TS of pericarp (En = endocarp; Ex = exocarp; H = hydrocytes; M = mesocarp; 

Rc = resin cell; Sc = seed coat). Fig. 40. Hedycarya cupulata. Pericarp. Fig. 41. Hedycarya dorstenioides. Pericarp. Figs 42, 

43. Mollinedia elliptica. Fig. 42. Pericarp. Fig. 43. Endocarp. Figs 44, 45. Wilkiea wardellii. Fig. 44. Pericarp. Fig. 45. Inner 

part of pericarp. Scale bars: Figs 40–42, 45 = 0.1 mm; Fig. 43 = 0.03 mm; Fig. 44 = 0.3 mm. 



The second zone (the mesocarp) is formed by 30–38 

layers of thin-walled cells, interspersed with numerous 

solitary or nests of 2–50 sclereids with thickened, 

lignified, striate, canaliculate cell walls. Most cells of 

the outer layers of the mesocarp are tanniferous and 

there are numerous solitary and nests of 2–15 tanniferous 

cells in the mesocarp. The inner 1–3 layers of the 

mesocarp are represented by tangentially elongate, 

ellipsoidal, thin-walled parenchymatic cells. The vascular 

system is situated in the second zone. The third 

zone (the endocarp) contains a single layer of thinwalled, 

tanniferous epidermal cells with an inconspicuous 

cuticle. 

Steganthera ilicifolia and S. fengeriana differ in 

pericarp thickness (up to 25–32 cell layers in 

S. ilicifolia; 50–60 cell layers in S. fengeriana) 

(Fig. 26). 

TETRASYNANDRA LAXIFLORA 

The numerous carpels develop into several stipitate 

drupelets. After anthesis the upper part of the floral 

cup abscises from the lower part so that the fruitlets 

are not covered during development. At maturity they 

are black and are presented on the reflexed yellow– 

green or yellow–orange remnant of the floral cup 

(Cooper & Cooper, 2004). The fruitlet outline is circular 

in TS. 


zones (Fig. 20). The first zone (the exocarp) 

consists of the one-layered epidermis of rather small, 

rectangular cells with thickened outer and inner tangential 

cell walls and an even, thin cuticle. The second, 

third and fourth zones are formed by the mesocarp, 

which consists of 85–100 cell layers. The second zone 

is represented by 1–2 layers of an interrupted hypodermis 

of small, somewhat ellipsoidal tanniferous 

cells. The third, most massive, zone is composed of 

large sclereid nests of 50–200 sclereids, which are separated 

from each other by several layers of thin-walled 

cells, and scattered spherical–ellipsoidal, thin-walled 

resiniferous cells. The central zones of the sclereid 

nests are formed by sclereids with thick, lignified, striate, 

canaliculate cell walls, from which numerous 

thin-walled sclereids radiate. There are also solitary 

or groups of 10–20 rather large, thin-walled, tanniferous 

cells. Some sclereids are also tanniferous. The vascular 

system is situated in the third zone. The fourth 

zone comprises 7–13 layers of large, spherical, thinwalled 

resiniferous cells, interspersed with scattered 

small, thin-walled cells. The inner 1–3 irregular layers 

of this zone are composed of pointed small cells. The 

fifth zone (the endocarp) is composed of a single layer 

of medium-sized, somewhat radially elongate (palisade) 

sclereids with unevenly thickened, lignified, 

striate, canaliculate cell walls; the radial walls are 

thickened more strongly. The cuticle of the inner epidermis 


MATTHAEA PUBESCENS 

The numerous carpels develop into numerous stipitate 

drupelets (Philipson, 1986: fig. 24, for M. sancta). 



during development. At maturity they are presented 

on the reflexed remnant of the floral cup 

(Philipson, 1986). The fruitlet outline is roundish– 

quadrangular in TS. 

The pericarp is differentiated into six distinct histological 


consists of the one-cell-layered epidermis of large, 

radially elongate, ellipsoidal, tanniferous cells of 

unequal size, and is covered by a very thick cuticle. 

The second, third, fourth and fifth zones are formed by 

the mesocarp, which consists of 20–33 cell layers. The 

second zone is represented by 1–3 layers of interrupted 

hypodermis of ellipsoidal tanniferous cells, 

interspersed with large spherical–ellipsoidal, thinwalled 

resiniferous cells. The third zone is represented 

by 7–10 layers of thin-walled parenchymatic cells, 

interspersed with numerous solitary and nests of 2–15 

sclereids with insignificantly thickened, lignified, striate, 

canaliculate cell walls. The fourth zone consists of 

7–21 layers of fusiform, tangentially elongate, thinwalled 

cells. The vascular system is situated in the 

fourth zone. The fifth zone is composed of a single 

layer of ellipsoidal, tangentially elongate cells with 

insignificantly thickened cell walls (supposedly the 

zone of hydrocytes). The sixth zone (the endocarp) is 

composed of a single layer of large, markedly radially 

elongate sclereids with thickened, lignified, striate, 

canaliculate, broadly wavy cell walls (Fig. 49). Some 

cells of the endocarp are somewhat ellipsoidal and are 

resiniferous. The cuticle of the inner epidermis is 


DISCUSSION 

COMPARATIVE FRUIT STRUCTURE AND RELATIONSHIPS 

WITHIN MONIMIACEAE S.S. 

Based on the anatomical differentiation of the pericarp, 

two general fruit forms were found in Monimiaceae 

s.s.: apocarpous drupelets with a more or less 

strongly developed putamen formed by the lignified 

endocarp and apocarpous berrylets. In addition, 

endocarp differentiation allows us tentatively to distinguish 

four different types of drupelets: 

1. Monimia-type (Fig. 50). The endocarp is differentiated 

into a very massive, many-cell-layered putamen 

(up to 55 layers of more or less isodiametric 



Figures 46–49. SEM micrographs of TS of pericarp (En = endocarp; Ex = exocarp; M = mesocarp; Rc = resin cell; 

Sn = sclereid nest). Fig. 46. Kibara coriacea. Fig. 47. Steganthera salomonensis. Figs 48, 49. Matthaea pubescens. Fig. 48. 

Pericarp. Fig. 49. Endocarp. Scale bars: Fig. 46 = 0.1 mm; Figs 47, 48 = 0.3 mm; Fig. 49 = 0.06 mm. 

Figures 50–53. Schematic TS of drupelets representing the four types here distinguished, ventral side up (endocarp grey, 

vascular bundles indicated). Fig. 50. Monimia-type (Monimia rotundifolia). Fig. 51. Hortonia-type (Hortonia floribunda). 

Fig. 52. Mollinedia-type (Mollinedia elliptica) (inset: close up of endocarp). Fig. 53. Hedycarya-type (Hedycarya dorstenioides) 

(inset: close up of endocarp). Scale bar = 1 mm. 



sclereids, which forms about three-quarters of the 

pericarp thickness). This type was found in Monimia, 

Palmeria and Peumus. 

2. Hortonia-type (Fig. 51). The endocarp is differentiated 

into a massive, many-cell-layered putamen 

(up to six layers of isodiametric, exceedingly thickwalled 

sclereids), which makes up less than onehalf 

of the pericarp thickness. The putamen may be 

differentiated into two lateral halves, i.e. with the 

sclerechyma partially interrupted on the ventral 

and dorsal sides (but without radial rows of small 

sclereids). This type was found in Hortonia. 

3. Mollinedia-type (Fig. 52). The endocarp is differentiated 

into a few-cell-layered putamen (two to several 

layers of more or less radially elongate 

sclereids with wavy cell walls). It forms less than 

half or less than one-fifth of the pericarp thickness. 

This type was found in Mollinedia, and to some 

extent in Kibaropsis (and Tambourissa). 

4. Hedycarya-type (Fig. 53). The endocarp is differentiated 

into a one-cell-layered putamen of usually 

pronouncedly radially elongate sclereids with wavy 

cell walls. It forms up to half of the pericarp 

thickness. This type was found in Hedycarya, 

Hennecartia, Levieria, Matthaea, Tetrasynandra 

and Wilkiea. 

The endocarp in Wilkiea wardellii is markedly 

reduced and is represented by relatively small cells 

with uneven U-shaped thickening of the cell walls. In 

Tetrasynandra laxiflora the endocarp is also notably 

weakly developed (but is still represented by rectangular 

palisade sclereids with lignified cell wall), and 

there are large concentric nests of sclereids in the 

mesocarp. The fruit of these two latter species could be 

viewed as transitional between drupelets and berrylets. 

The apocarpous berrylets lack sclerified (lignified) 

cells in the endocarp (there is only a single layer 

of thin-walled cells) but also contain large nests of 

sclereids in the middle zone of the mesocarp. They are 

characteristic of Kibara and Steganthera species (see 

also Bobrov et al., 2003b). 

In contrast to the Hortonia-type, in the drupelets of 

the Mollinedia-type, the endocarp cells are somewhat 

radially elongate and their lignified walls are wavy. 

This provides more intensive contact between the cells 

and therefore potentially increased protection of the 

seeds from dispersers, such as birds. The number of 

endocarp cell layers in the Mollinedia-type is about 

the same as or more than in the Hortonia-type. Reduction 

in the number of cell layers of the endocarp to one, 

but with more pronounced elongation of cells in the 

radial direction together with the differentiation of 

conspicuously wavy cell walls may have given rise to 

the Hedycarya-type of drupelets. The Hedycarya-type 

may be the most advanced of all drupelets in the Monimiaceae 

studied, and a number of variations of the 

single-cell-layered endocarp structure can be observed 

as to different size and form of cells and thickness of 

cell walls. Fruitlets as in Kibaropsis may be viewed as 

intermediate between the Mollinedia-type and the 

Hedycarya-type. If the Mollinedia-type is more ancestral 

than the Hedycarya-type, the latter may have 

arisen twice or more: in South America and again in 

Australasia, as based on molecular analyses (Renner, 

1998, 2002) the South American Hennecartia appears 

to be related to Mollinedia, whereas the Old World 

Kibaropsis is probably related to Hedycarya and Levieria. 

Tetrasynandra laxiflora (but not the other Tetrasynandra 

species) should probably be included in 

Steganthera based on floral structure (P.K.E., unpubl. 

data). This may be concordant with unusual 

endocarps: single-layered, markedly reduced sclerenchymatic 

endocarp in the former, and single-layered 

parenchymatic endocarp in the latter. However, these 

interpretations of fruit relationships within Mollinedioideae 

remain tentative as long as the phylogenetic 

relationships are not clearly resolved. 

Of special interest is that the distinction of three 

major clades in Monimiaceae s.s., (1) Peumus + Palmeria 

+ Monimia (Monimioideae), (2) Hortonia (Hortonieae 

of Mollinedioideae), and (3) the remainder of 

Mollinedioideae, as shown by molecular phylogenetic 

studies (Renner, 1998, 1999, 2002), is also well supported 

by the present carpological and other structural 

data (Philipson, 1993; Romanov & Bobrov, 2002; 

this study). Monimioideae (clade 1) are characterized 

by the Monimia-type of drupelets, Hortonieae of Mollinedioidae 

(clade 2) by the Hortonia-type, and the 

remainder of Mollinedioideae (clade 3) by the Mollinedia-type 

and Hedycarya-type or, in the extreme, by 

berrylets. The fruits of Hortonia also differ from the 

other genera of Mollinedioideae by their fruitlet shape 

as seen in TS, which is elliptic (with smaller diameter 

in lateral than in median direction) in Hortonia and 

circular in the other Mollinedioideae. 

COMPARISON OF FRUITS OF MONIMIACEAE S.S. WITH 

THOSE OF OTHER BASAL ANGIOSPERMS 

Close relationships of Monimiaceae and Lauraceae 

have long been recognized (Takhtajan, 1966, 1997; 

Endress, 1972, 1980b; Cronquist, 1981; Philipson, 

1993), and were supported by molecular phylogenetic 

studies (Renner, 1999; Qiu et al., 1999, 2005; Renner 

& Chanderbali, 2000; Soltis et al., 2000), and also by 

combined molecular and morphological phylogenetic 

studies (Doyle & Endress, 2000; Doyle, 2005). The carpological 

data presented here also support this interpretation. 

Although in Lauraceae, in contrast to 

Monimiaceae s.s., the gynoecium is consistently monomerous, 

and the floral cup is commonly less pro- 



nounced (Kostermans, 1957; Endress, 1980b; Hyland, 

1989; Rohwer, 1993), the anatomical structure of some 

lauraceous fruits is similar with the Hedycarya-type of 

fruitlets of Monimiaceae s.s. The most prominent character 

of these fruit(let)s is that their endocarp is 

formed by a single layer of palisade sclereids with 

thickened, lignified walls (Melikian & Dzhalilova, 

2003) (Fig. 27). Thus, the two families appear to share 

an apomorphic trend in fruit structure. It would be of 

interest to know more about the fruits of the ’basal’ 

Lauraceae, Hypodaphnis and Cryptocaryeae (Rohwer 

& Rudolph, 2005). 

Siparunaceae and Gomortegaceae are two other 

families of Laurales with drupe(let)s. In Gomortegaceae 

the two to three united carpels form a fruit with 

a thick and extremely hard stone (Heo et al., 2004). In 

Siparuna (Siparunaceae), the free carpels develop into 

drupelets (Corner, 1976; Kimoto & Tobe, 2003). In 

most species, the floral cup of the mature fruit splits 

into irregular valves, and the drupelets are presented 

on the inside of the opened floral cup, and, together, 

they form a colour contrast, comparable with the 

fruits in Monimia, Palmeria and Hennecartia. In addition, 

the drupelets form a coloured fleshy outgrowth, 

which further adds to the colour contrast, and the 

fruitlets look like seeds with an aril (Endress, 1973; 

Renner & Hausner, 1997). Only in few Siparuna 

species does the floral cup never dehisce (Renner & 

Hausner, 2005). 

In contrast to the similarities in fruit morphology 

and anatomy between these four families of Laurales 

(particularly between Monimiaceae s.s. and Lauraceae), 

fruit anatomy of these families considerably 

differs from that of basalmost angiosperms (ANITA 

grade), despite superficial resemblances. In Amborella, 

the hard part of the fruitlets is mainly formed by 

a massive sclerified layer of the mesocarp, whereas the 

sclerified endocarp is only thin (Bobrov et al., 2005). In 

addition, lignification of these sclerified cells is lacking 

or occurs only in late developmental stages. Fruit 

anatomy of Nymphaeales is poorly known. However, 

they do not seem to be sclerified, as maturation and 

seed dispersal is under water. Fleshy-fruited Austrobaileyales 

do not have sclerified layers in the pericarp, 

only in the seed coat (Austrobaileyaceae, 

Endress, 1980c, 1983; Trimeniaceae, Endress & Sampson, 

1983; Bobrov et al., 2002; Schisandraceae, Saunders, 

2000; Denk & Oh, 2005). The same is true for 

Chloranthaceae (Endress, 1987), the phylogenetic 

position of which is not yet settled (Doyle & Endress, 

2000; Qiu et al., 2005). In contrast to Laurales, in 

which the endotesta commonly appears to be sclerified 

in the seed (Kimoto & Tobe, 2001), in basalmost 

angiosperms either the exotesta (Nymphaeales, Austrobaileyales 

pro parte) (Corner, 1976; Melikian, in 

Takhtajan, 1988) or the mesotesta or both (Austrobaileyales 

pro parte) (Melikian, in Takhtajan, 1988; 

P.K.E., pers. observ.) is sclerified, or the seed coat is 

not sclerified (Amborella) (P.K.E., pers. observ.). 

In the context of the entire basal angiosperms, 

drupes or drupelets appear to be rare (Endress, 1996). 

Fleshy fruits commonly do not form a putamen 

(Takhtajan, 1988; Romanov, 2004; for other Laurales, 

see Mohana Rao, 1986; for Magnoliales, see Endress, 

1983; Mohana Rao, 1983; van Setten & Koek- 

Noorman, 1992; Melikian, Bobrov & Romanov, 2002). 

Exceptions, in addition to the Laurales discussed here, 

are some Piperaceae (Piperales) with a thin, sclerified 

endocarp (e.g. Kanta, 1962; Palmarola Bejerano, 

2003), and Himantandraceae (Magnoliales), in which 

each mature carpel has a separate putamen (e.g. 

Endress, 1983); however, fruit development of the latter 

has not been studied as yet. 

In general, fruit anatomy and development in basal 

angiosperms are understudied (Endress, 1996). This 

and other studies show the promising systematic 

significance of these reproductive traits in basal 

angiosperms (Romanov, 2004). Not only may superficially 

similar fruits of unrelated taxa reveal anatomical 

differences, as discussed above, but also the 

reverse may be found. For example, achene-like fruitlets 

of Atherospermataceae differ strongly from drupelike 

fruitlets of other Laurales in their superficial 

appearance and mode of dispersal. Nevertheless, the 

anatomical structure of their pericarp is similar to 

that in Monimiaceae s.s. and Lauraceae; although the 

pericarp is thin and dry, the endocarp is always represented 

by one or two cell layers with thickened, lignified 

cell walls (Bobrov et al., 2003a; Bobrov, Sorokin 

& Romanov, 2004). Another example of apparent anatomical 

conservatism despite fruit diversity is provided 

by the Rhamnaceae (Vikhireva, 1952). In 

general, it appears that there is much convergence in 

superficial mature fruit structure, whereas fruit 

anatomy and development reveal more features of 

systematic significance (e.g. Melikian, 1996). Better 

knowledge of fruit anatomy of extant plants will also 

help to integrate more intensively fossil fruits into systematic 

and evolutionary studies of angiosperms. 

ACKNOWLEDGEMENTS 

We thank David H. Lorence for providing pickled 

fruits of Tambourissa tau and for information on Monimieae. 

Rosemarie Siegrist is thanked for microtome 

sections, and Alex Bernhard for support with some 

illustrations. We thank Nina B. Sheremet and Alexander 

Sennikov for assistance with the collection of 

fruit samples. Wilhelm Barthlott is thanked for Figure 

2. The study was supported by the Russian Foundation 

for Basic Research (grants # 05-04-49204-a and 

05-04-49143-a). 



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APG (The Angiosperm Phylogeny Group). 2003. An 

update of the Angiosperm Phylogeny Group for the orders 

and families of flowering plants: APG II. Botanical Journal 

of the Linnean Society 141: 399–436. 

Baillon H. 1867–69. Histoire des Plantes, Vol. I. Paris: L. 

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