Manihot Manihotoides (Euphorbiaceae) - CNCFlora

Systematic Position of the Genus 65
usually 7.0-10.0 cm long, glabrous, terete, ventral surface dark dull red, dorsal surface
greenish; lamina peltate, over 0.5 cm wide at the region between the petiole attachment
point and the lamina margin at the base of the leaf, ventral lamina deep green, dorsal
lamina markedly glaucescent, abaxial surface wax pattern smooth; venation craspedodromous;
palmately 5 lobed, 3 major and 2 smaller lobes; median lobes ovate-ellipsoid to
more or less parabolic, pandurate, rarely entire-lobed, usually 5.0-10.0 cm long, the basal
lobule apex abruptly dilated, cuspidate, terminating in a spine-like point; lamina margin
above and below the basal lobule incised, often deeply, into lobulets which also terminate
in spine-like extensions, apex acute to acuminate; the sinuses on either side of the median
lobe with a characteristically flat base forming an almost 45? angle to the median lobe
midrib; lowest lobes about half as long as median lobes, apex cuspidate. Inflorescence a
monoecious, axillary, subspicate, raceme, 5.0-10.0 cm long, all parts glabrous; bracteoles
setaceous, less than 0.3 cm long, glabrous, margin serrate; bractlets setaceous, glabrous.
Pistillate flowers restricted to the very base of the inflorescence, borne on ca 1.5 cm long
pedicels (which appear attached directly to stem); tepals ca 1.1 cm long, light purplish
streaked externally, cleft to the base into 5 oblong-lanceolate lobes; disc fleshy, entire,
with several staminodes; pistil ca 0.6 cm long, ovary subglobose, the trifid stigma well
lobed and lobulate. Staminate flowers almost tubular, distinctly constricted in the
middle, tepals ca 1.2 cm long, light purplish streaked externally, cleft 1/3 of the way
down into 5 lobes, the lobes oblong, tapering, not prominently reflexed at anthesis; disc
fleshy, 5 lobed; stamens 6-10 (6, 7, and 8 observed, 10 reported in original description),
superior whorl ca 0.9 cm long, inferior whorl ca 0.7 cm long, filaments and anthers cream
colored. Fruit pedicels slightly curved downwards ca 1.5 cm long, pistillate pedicels
attached to the very base of the inflorescence; capsules almost globular, ca 1.0 cm long
from base to apex, surface sparingly but manifestly verrucose and rugose, ribs not
prominent; fruit dehiscence septicidal. Seeds rotund, ca 0.8 cm long; caruncle very
prominent, large in comparison to seed size, ca 0.2 cm long and ca 0.4 cm broad, cream
colored, slightly cleft and 2 lipped in front. Fig 21A, B, C, D.
TYPE. Walker (Parks, H. B.) s n: USA, Texas: Mission, 1940 (holotype, A; isotypes,
A-2).
DISTRIBUTION. (Fig 20D). USA: Texas; Mexico: Tamaulipas. USA. Texas: Rogers 522
(F, G, NY, US) University of Texas, Austin, 31 Aug 1967;Schott 52 (F-2, NY-2) Ringgold Barracks, 2
Jun 1853; Walker 1003 (GH) La Joya, Apr 1940; Wornock & Barkley 147 (MO, UC, US) University of
Texas Campus, 7 Jun 1943. MEXICO. Tamaulipas: Crutchfield & Johnston 5572 B (TEX) Papalote de
Mirandena, 16 Sep 1960; Johnston 5363B (TEX) Rancho Loreto, 26 Apr 1960; Pringle 2243 (GH)
near Matomoros, 31 Jul 1888.
This distinct species may be very close to extinction in the localities along the Rio
Grande in Texas and adjoining Mexico due to intensive cultivation in this area. The
illustrations, and much of the detailed description of Manihot walkerae were taken from
the small but vigorous colony established on the south side of the Department of Botany
building at the University of Texas, Austin, Texas.
3. Manihot sect Foetidae Rogers & Appan, sect nov
Manihot sect Grandibracteatae Pax subsect Papillosae Pax in Engler, Pflanzenreich IV. 147(Heft
44): 28. 1910.
Plantae caulinae, lignosae arbores. Folia petiolatae, penitae lobatae inflorescentia
monoecia panicula.
Plants caulescent; leaves widely spaced on stem; petiolate, petiole attachment basal
or peltate; lamina membranaceous to coriaceous, deeply lobed, lobes variously shaped but
not linear. Inflorescence a monoecious panicle; bracts and bracteoles setaceous or
semifoliaceous, margins usually entire.
TYPE. Manihotfoetida (H.B.K.) Pohl.
DISTRIBUTION. (Fig 22).