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84 FIELDIANA: BOTANY, VOLUME 28
other narrower, dark brown bands occur elsewhere on the segment,
the lower surface covered with numerous, microscopic, sessile,
deep brown scales, strongly sulcate above and conspicuously ribbed
below; terminal segment cuneate, shallowly and irregularly erose
at apex, 50 cm. long; middle and lower pinnae narrowly ligulate,
obliquely praemorse and shallowly erose along apex, up to 16- nerved
on lower surface, but often with only 3-5 strong nerves, the dark
brown, tomentose, marginal band 4-8 mm. wide; spadices unisexual,
arising on trunk at base of leafy shoot, white; staminate spadix with
numerous branches, the branches slender with crowded staminate
flowers; staminate sepals broadly depressed-rounded; staminate
petals separate and free to the base, the margins pale; pistillate
spadix covered minutely with short whitish tomentum; pistillate
sepals depressed-suborbicular; staminodia attached at base of
ovary (Fig. 11).
Type in herb. Chi. Nat. Hist. Mus., collected on southeast-facing
slopes of Ptari-tepuT, state of Bolivar, alt. 1585-1600 m., November
10-11, 1944, Julian A. Steyermark 60044.
Local name: "Puru-a-yek". This is one of the dominants of the
understory of the moist forest covering the southeast-facing slopes
of Ptari-tepuT. The inside of the shoot is not edible.
The characteristics of this new genus are the occurrence of the
pistillate and staminate flowers in separate spadices, the pistillate
flowers much smaller than in Socratea, Iriartea, Dictyocaryum,
Catostigma, or Catoblastus, the entire glabrous ovary with apical
stigmas, the very small staminate flowers with separate petals not
spreading and not dilated or gibbous at base, and the 6 stamens.
In Dugand's key to the Iriarteae (Caldasia 1: 33-34. 1940), this
plant does not fall either section. into^
He has "Flores de ambos
sexos en el mismo espa'dice; ovario entero, de estigmas apicules o
excentricos", which includes Socratea, Iriartea, Iriartella, Dictyocaryum,
and Cuatrecasea, as opposed to "Flores de cada sexo en
espadices, separados", which includes Catoblastus, Catostigma,
Wettiniicarpus, and Wettinia. Our collection would fall in the latter
group. However, that group has the "ovario casi siempre trilobulado
(1 o 2 lobulos mas pequenbs abortivos) a menudo pubescente o
velludo, con estilo o estigmas basilares o sobre los lobulos basales;
palmeras medianas o elevadas", whereas our collection has "ovario
entero, de estigmas apicales o excentricos" which would place
it
wkh Socratea, Iriartea, and Dictyocaryum.
Like Dictyocaryum our collection has 6 stamens, entire ovary with
apical stigmas, 6 staminodia, and the segments of the leaves quite
laciniate in different directions; however, unlike that genus, the
staminate and pistillate flowers are in separate spadices, the pistillate
flowers are much smaller, and the staminate sepals are not
dilated or gibbous at the base, and are much broader than long. In