l - CNCFlora

Volume 91, Number 4
2004
Croat
Revision of Dieffenbachia
other family is so poorly known taxonomically. with the lowest totals just north of the San Juan
Plants exhibit considerable morphological plasticity depression (Nicaragua), followed by a marked inat
all stages of development. Many of the genera, crease approaching the South American continent.
especially the hemiepiphytic genera Rhodospatha (In this treatment, Central America is defined as all
Poepp., Monstera Adans., and Syngonium Schott, the area between Mexico and Colombia, whereas
exhibit complex patterns of heterophylly, with dras- Middle America is all the area between Mexico and
tically different morphology at different stages of Panama.) Mexico has 2 species, Guatemala (2), Bedevelopment
(Croat, 1981 [1982]; Ray, 1981, lize (1), Honduras (3), E1 Salvador (2), Nicaragua
1987). Most members of the family have succulent (6), Costa Rica (13), and Panama (20) (Table 1).
parts, making them difficult to collect and preserve. Endemism is high, especially in Costa Rica with 3
Dieffenbachia is one of several medium-sized endemic species and Panama with 9. A total of 7
genera in the Araceae, with an estimated 135 spe- species are shared between Panama and Costa
cies. This revision is the first major review of Dief- Rica. Just under one-third (31Wo) of Central Amerfenbachia
for Central America since Adolf Engler's ican species of Dieffenbachia range into South
(1915) generic treatment in Das Pf anzenreich. America, these being D. davidsei, D. isthmia, D.
Dieffenbachia is one of the most important genera killipii, D. Iongispatha, D. nitidipetiolata, D. obscuof
understory herbs in the family, and it is often a
dominant component of humid to wet tropical forrinervia,
D. seguine, and D. tonduzii.
ests, especially from sea level to 1500 m. It inhabits
life zones ranging through Premontane moist for-
MATERIALS AND METHODS
est (P-mf), Tropical moist forest (T-mf), Premontane This revision is based on more than 29 years of
wet forest (P-wf), Tropical wet fore.st (T-wf), and Pre- field studies in Central and South America, bemontane
rain forest (P-rf) (Holdridge, 1967). While tween 1967 and 1996. All but one species were
most spevies occur in virgin humid forests, the ge- studied live in the field or under cultivation at the
nus is known from freshwater swamps, stream Missouri lAotani(al Garden. The descriptions have
tanks, reglowth forest, among lo(k out(rosX aIl(l I)een prepale(l flom }oth living and drie(l spe(io(easionally
on roa(l l)anks. It often ( onstitutes the mens. The ex(el)tion is D. fo.steri, where the demost
tonsl)i(uous elelllent of the un(lelstoly vege- s(ril)tioll was lase(l solely on the tyl)e sI)e(inen.
tation })e(ause of its a}un(la-l(e, fe(luellt (olollial rRle use of ("(llie(l") pre(e(lillg a11 or any lart of
glowth 11a}it, an(l genelully ]aIge, showy leaves. the des( ril)tioll is an in(lie ation tllat a11 that follows
The genus t)IOVi4eS a wi(lP valiely of (hoi(e orlla- is lase(l oll let })al iuln nlatel ial ollly. Mol l)hologi( al
mental plants for horti( ulture, in( lu(ling nlost of the (hala(tes wee *o(le(l dire(tly into a (oml)uterize(l
ST)et ieS treate,(l he,l e.
data})ase to ensule parallel an(l sortal)le (lescriy)-
The genus is (listine t an(l not easily ( onfuse(l tions. 'I'he aloi(l dese liptions (latalease ( ontains 72J4
with any other aroi(l. It is ( losest to Bog7lera, whie h c halae tel states aplicable to the morphologie al didiffers
in la(king staminodia sulrounding the pis- versity exlesse(l in DiefWenh(leSli(l (Croat, 1997).
tillate flowers and in having higher-order venation Dis(ussions and references to illustrations, as well
reticulate. In contrast, Dieffenb(lchi(l has several as exsi(catae, are stored separately, but tie(l to a
staminodia surrounding the pistils and higher-order particular spee ies description and to the nomenclavenation
parallel-pinnate. However, the monotypic tural information by a unique taxon number. Tergenus
Bognera is endemie to Brazil, and it is not minology and usage in the descriptions in this relikely
to be a problem with determination of most vision are largely defined by Croat and Bunting
Dieffenbachia. Alternatively, DiefJenbachia is fre- (1979) and elaborated in Croat (1997).
quently confused with Philodendron Schott, partic- Ecological zones, though sometimes estimated
ularly the terrestrial species of the latter with non- from my own experience with Central American
cordate blades. Philodendron species are mostly vegetation, are largely taken from Holdridge lifehemiepiphytic,
rarely terrestrial as is Dieffenbachia. zone maps (Holdridge, 1967; Holdridge et al.,
Even when Philodendron species are terrestrial and 1971), where they exist for Central American counhave
non-cordate blades, they can be distinguished tries, and for Mexico from the "Mapa de tipos de
by the remotely many-flowered pistils that are not vegetacion de la Republica de Mexico" (Flores et
surrounded by staminodia, as well as the lack of al., 1971).
the acrid foul-smelling, irritating sap that is so Herbarium material has been widely distributed
closely associated with Dieffenbachia.
and original field vouchers are cited for all herbaria
Species diversity of Dieffenbachia shows a gen- whose material was seen (see Appendices 1, 2).
eral diminution from Mexico to Middle America Herbarium material may consist of one of three
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