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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
BOTANICAL EXPLORATION IN VENEZUELA - I 85 Dictyocaryum the staminate sepals are narrower and much longer than broad. It will be observed that the segments of the fronds in Dahlgrenia are narrow, because they have become split at maturity apparently into five narrow divisions, whereas actually it may represent just one leaf segment up to 21 cm. wide that has become split into portions from 3-5 cm. wide. On such a wide leaf the brown bands may number as many as nine, but when each segment splits lengthwise of the whole of which it is a part, these brown bands then appear marginal, with the result that there may be up to twenty-five main nerves extending lengthwise, these becoming fewer in number as the segment becomes split. Desmoncus duidensis Steyermark, sp. nov. Scandens vel subscandens; frondis vagina inermi fusco-furfuracea; fronde 0.78 m. longa; flagello tenui 20 cm. longo, foliolis hamatis 4-jugis rectis 12-25 mm. longis, 1-1.5 mm. latis, aculeis brevibus retrorsis curvatis 1.5 mm. longis fusco-furfuraceis; rhachi tenui 2-3 mm. crassa fusco-furfuracea aculeis retrorsis brevibus viridibus vel stramineis praedita; pinnis oppositis 4-jugis sessilibus oblongoellipticis ad apicem acuminatis ad basim nonnihil angustatis 12.5-16 cm. longis, 3.5-6 cm. latis, supra glabris, infra minute fuscomaculatis vel punctatis, ad margines fusco-furfuraceis 2 mm., firme membra naceis. Low climbing or sprawling plant; frond dark green above, dull paler green below. Type in herb. Chi. Nat. Hist. Mus., collected in forest along Base River (Cano Negro), at southeastern base of Cerro Duida, Territorio Federal Amazonas, alt. 225 m., August 23, 1944, Julian A. Steyermark 57944. Desmoncus duidensis is distinguished by the few pairs of oblongelliptic sessile opposite pinnae, the slender, short, few pairs of straight barbs of the cirrhus, the unarmed leaf sheaths and leaflets, the minutely aculeate rachis, and the brown-furfuraceous margins. From D. nemorosus Barb, it differs in the unarmed leaf sheath, shorter more slender barbs of the cirrhus, and the fewer leaflets, which are not aculeate on the lower surface of the midrib. From D. aereus Drude it may be distinguished by the shorter, more slender, fewer barbs of the cirrhus, and by the short-aculeate rachis. Desmoncus maltijugus Steyermark, sp. nov. Scandens; frondis vagina pallido-viridi, tomento flavo-cinereo, setis fuscis confertis 2-15 mm. longis; fronde 1.7 m. longa brevipetiolata; petiolo 1 cm. longo; flagello 50 cm. longo, foliolis hamatis 6-jugis oppositis rectis robustis, 1.3-5 cm. longis, 3-4 mm. latis, rhachi inermi; infra foliola hamata 2 foliolis aliis longioribus retrorso-patentibus 7.5-10 cm. longis; frondis rhachi utrinque fusco-
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o 2 CM XI E> RAR.Y OF THL UNIVERSIT
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FIELDIANA: BOTANY A Continuation of
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NUMBER 1 LIST OF ILLUSTRATIONS TEXT
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PAGE 67. Emmotum ptarianum 342 68.
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CONTRIBUTIONS TO THE FLORA OF VENEZ
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BOTANICAL EXPLORATION IN VENEZUELA
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