Lagenocarpus sabanensis Gilly
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Authority
Maguire, Bassett. 1965. The Botany of the Guayana Highland. Mem. New York Bot. Gard. 12 (3): 1-285.
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Family
Cyperaceae
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Scientific Name
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Type
Type. Sabana Grande, southeastern base of Cerro Duida, alt. 200 m, Amazonas Venezuela, Jidian A. Steyermark 57855 (F, holotype).
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Description
Latin Diagnosis - [Descr. emend. & amplif.] Rhizome short, ascending, thickly clothed with brown fibrous remains of basal sheaths; underground stolons elongated to 15 cm, 5 mm thick, surrounded by brown lanceolate scales about 2 cm long. Culm solitary, central, 80-150 cm tall, trigonous, 3-5 mm thick below, puberulent, 4-6-nodose. Leaves radical and 2 to 4 upper on the culm; the blades narrowly linear, straightish, stiff, folded, 60-90 cm long, 5-7 mm wide, puberulent, very glaucous beneath, gradually attenuate toward very sharp apex; sheaths 3-4 cm long, brown or purplish-brown; contra-ligules broadly deltoid, 2.5-4 mm long, acutish or obtusish. Inflorescence a slender terminal compound panicle, more or less interrupted or contiguous, 50-70 cm long; the lower 2 to 4 partial panicles staminate with pendant slender fascicled branches, long-exserted and rather spreading; the upper 2 or 3 partial panicles pistillate with erect, relatively short branches. Staminate spikelets oblong, 3.5 mm long; glumes several, oblong-elliptic, 2.5 mm long, with a short awn at apex; stamens 2 or 3. Pistillate spikelets ellipsold at maturity; glumes 4 to 6, imbricate, broadly ovate to suborbicular-obovate, 2.5-3 mm long, about 2 mm wide, thickly chartaceous to thinly coriaceous, tawny or cinnamon-colored, rounded to shallowly emarginate at apex, ciliate on margins, the awn short, upright. Fructifications ovoid (rarely broadly ovoid), 4-4.5 mm long, 2-2.2(-2.6) mm wide, terete, inconspicuously trigonous, brownish-yellow, the lower part with 3 large dark brown moles, the upper part (= beak) thickly conical, abruptly pointed at apex, wholly glabrous; stigmas 3.
Distribution and Ecology - Distribution. Western part of Venezuela, Mt. Duida and westward, and eastern Vaupes, Colombia.
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Discussion
This good species had already been collected by Tate from the Mt. Duida region some 30 years before it was described by Gilly based on a Steyermark collection. L. sabanensis is, as indicated by Gilly, more or less related to L. guianensis particularly in the character of fructifications. But, the fructifications are definitely larger than those of L. guianensis and have three large moles below the middle, suggesting also the taxonomic afiinity with L. rigidus. Since Gilly's original description was based on a specimen without any mature fructification the description, drawn from the additional collection, is here amended and amplified.