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236 FIELDIANA: BOTANY, VOLUME 28
slopes, Ptari-tepui, state of Bolivar, alt. 1585-1600 m., November
10-11, 1944, Julian A, Steyermark 60014 (2 sheets, staminate and
pistillate), "shrub 10 feet tall; leaves coriaceous, dull green above,
pale green below; perianth dull yellow".
In the staminate flowers the 2 inner divisions of the perianth are
thickened within, and have more or less three irregularly toothed and
denticulate-thickened callosities running lengthwise along the inner
margins and irregularly denticulate at the apex. The appendages of
the inner divisions of the staminate flowers are thinner than the rest
of the perianth but not conspicuously elongated.
This species is apparently a member of Sect. Appendiculatae Perk,
and is related to M. LowtherianaPerk. of Brazil. From that species
it
may be distinguished by the 20 densely hispidulous carpels, the
rounded tips of the pistillate perianth divisions, larger pistillate
flowers, 13-14 stamens, more coriaceous broader subentire leaf
blades which are minutely appressed-pubescent on the lower surface,
and longer petioles.
Mollinedia roraimensis Steyermark, sp. nov.
Frutex, ramis subteretibus, novellis fulvo-tomentosis; foliis oppositis
petiolatis ovatis vel elliptico-ovatis, basi subacutis, apice
abrupte acuminatis, remote denticulatis, coriaceis, 15-18 cm. longis,
6-9 cm. latis, supra glabris, subtus subtomentosis, nervis 5-6 jugis;
petiolis 12-15 mm. longis, plus minusve subtomentellis; floribus
non visis.
Type in herb. Chi. Nat. Hist. Mus., collected on southwest-facing
forested slopes of Mount Roraima, between Rondon Camp and base of
sandstone bluffs, state of Bolivar, alt. 2040-2255 m., September 30,
1944, Julian A. Steyermark 59004, "shrub 8 feet tall; leaves coriaceous,
dark green above, pale green and velvety below; stems
purple-brown pubescent".
Although this plant was found in only sterile condition, it apparently
represents an undescribed species that may be distinguished from
the closely related and above described A/, ptariensis by the denticulate
leaves, which are more densely pubescent on the lower surface
with longer trichomes.
Siparuna Pittieri Steyermark, sp. nov.
Frutex dioecus, 3 m. akus; ramis tomentulosis, pilis stellatis
luteo-fulvis; foliis elliptico-obovatis, 15-32 cm. longis, 7-13 cm.
latis, apice subito acutis vel acuminatis, basi rotundatis vel obtusis,
minute et remote denticulatis, utrinque stellato-tomentosis; petiolis
1.5-6 cm. longis, dense fulvo-tomentosis; inflorescentia tomentulosa,
gracili, foeminea 1.5-2 cm. longa; receptaculo foemineo globosourceolato
fulvo-tomentoso in diametro 3.5; stylis 4 exsertis, inferne
in columnam coalitis.