Manihot Manihotoides (Euphorbiaceae) - CNCFlora

82 Flora Neotropica
towards the apex, apex acuminate, base of lobes less than 0.5 cm wide, lamina between
base of sinus and petiole-midrib junction less than 0.5 cm wide; lowest lobes alternate
usually ca 1/4 as long as median lobes. Inflorescence a monoecious, medium sized,
panicle, ca 9.0 cm long, flowers clustered at the terminal regions of peduncles, lower half
of the rachis usually devoid of flowers, all parts glabrous, bracteoles and bractlets
setaceous, ca 1.0 cm long. Pistillate flowers restricted to the base of the upper half of the
inflorescence, pedicel ca 1.0 cm long, tepal less than 0.5 cm long, ovary subglobose.
Staminate buds ovoid-ellipsoid, flowers small, less than 0.5 cm long, cleft ca 1/3 down
into 5 lobes, stamens 10 arranged in 2 whorls of 5 each. Fruits non vidi. (Fig 31 A, B).
TYPE. Rombouts 464: Suriname: upper Sipaliwini R., 9 Feb 1936 (holotype, U;
isotypes NY, MO).
DISTRIBUTION. (Fig 30D) Venezuela, Guyana and Suriname, in savannas. Specimens
doubtfully assigned to Manihot surinamesis: VENEZUELA. Guayana, Cardona 1158 (F, NY, US,
VEN), sabanas del Rio Uriman, afluente del Caroni, alt 400 m, May 1945. GUYANA. Lanjouw &
Donselaar 789 (U), Rupununi Savanna, in directionem borealem de montibus Kanuku, 16 Feb 1959.
SURINAME. Rombouts 409 (U-2, US), upper Sipaliwini R., Camp XVIII near 4 Gebroeders.
Jennings (1959) mentions the use of Manihot melanobasis in breeding experiments
with cassava in East Africa. It is clear that there was a misdetermination in case of the
actual plants that were used in the experiments, because we have determined from the
type material that M. melanobasis is a synonym of M. esculenta. From the description of
the plants actually used by Jennings and from the geographic region from which the
breeding material was collected we believe that M. surinamensis was the species used. It is
unfortunate that documenting herbarium specimens of materials used by plant breeders
are seldom collected and as a result the breeders work cannot be affirmed.
22. Manihot tristis Mueller von Argau in Martius, Fl. Bras. 11(2): 449. 1874.
Shrubs, to 3.0 m tall. Young stems pubescent or glabrous; mature stem glabrous.
Leaves alternate; stipules persistent or caducous, margin serrate; petioles 4.0-9.0 cm long,
glabrous or pubescent; lamina palmately 3-5 lobed, glabrous or pubescent, abaxial
surface wax pattern reticulate; venation camptodromous, median lobes obovate, usually
5.0-10.0 cm long, occasionally longer, ca 2.5 cm wide, apex acute, base of lobe narrow
(less than 0.5 cm) to wide (more than 0.5 cm). Inflorescence a monoecious panicle, less
than 8.0 cm long; bracteoles and bractlets setaceous. Pistillate flowers restricted to the
base of the panicle, pedicel ca 2.0 cm long, tepal 0.6 cm long, deeply cleft into 5 lobes,
ovary subglobose. Staminate buds ovoid-ellipsoid, 0.5 cm long, cleft ca 1/3 way down
into 5 lobes, stamens 10, in 2 whorls of 5 each.
DISTRIBUTION. (Fig' 31C). Venezuela, Amazonas Territory; Suriname; Brasil, Ama-
pa and Roraima Territories. One subspecies, M. tristis subsp saxicola, is found on granitic
domes, and in this respect, is similar to M. leptopoda, (species No. 28) which grows on
granitic outcrops in the Rio de Janeiro region.
The "skyline" (Fig 28) indicates that the plants here related as subspecies should be
kept distinct. It is at this point, however, that the taxonomist's judgment must be
exercised, and in this example, we overruled the computer-made relationship. Actual
reexamination of the specimens, and the geographic distribution (Fig 31C) indicated the
relationship here given.
Key to the Subspecies of Manihot tristis
1. Petiole attachment basal; leaf lobe base very narrow, less than 0.3 cm wide.
22a. M. tristis subsp tristis.
1. Petiole attachment peltate; leaf lobe base more than 0.3 cm wide.
2. All parts glabrous.
22b. M. tristis subsp saxicola.
2. Leaf lobes, petioles, young stems, stipules, bracts, tepal etc pubescent.
22c. M. tristis subsp surumuensis.