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(Last Modified On 10/24/2013)
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Species
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Aulonemia chimantaensis Judziewicz & Davidse
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Note
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TYPE: Venezuela. Bolivar: Dist. Piar, altiplanicie en la base meridional de los farallones superiores del Apacara-tepui, "drier part of savanna bordering large swampy sa- vanna," 5'20'N, 62'12'W, ca. 2,200 m, 30 Jan.-1 Feb. 1983 (fl), J. A. Steyermark, 0. Huber & V. Carreno 128369 (holotype, MO; isotypes, ISC, K, SP, US, VEN).
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Description
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Woody bamboo; culms to 1.5 m long, erect, smooth. Culm leaves not seen. Midculm nodes bear-
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Habit
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Woody bamboo
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Description
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ing single, divergent branches. Foliage leaves with sheaths glabrous below, strigose on the back near the summit; oral setae 1-2 cm long, brown, few, restricted to the summit; outer ligule 0.3 mm long, indurate; inner ligule ca. 1 mm long, membranous; pseudopetioles 4-6 mm long, dark purple; blades 11-14 cm long, 1.5-3.5 cm wide, often deflexed, narrowly to broadly lanceolate, obtuse at the base, acuminate at the apex, glabrous above, puberulent and scaberulous beneath, the margins with scattered prickles. Peduncle 5-15 cm long, slender, antrorsely scabrous. Inflorescence 22-28 cm long, an open, ovoid panicle; branches 6-10 cm long, loosely ascending, slender. Spikelets (1.3-)2.2-4 cm long, 1.8-2.5 mm wide, linear, slightly curving, densely 9-15-flowered, the florets imbricate; glumes pur- plish, firmly membranous, glabrous; lower glume 1.5-2.7 mm long, lanceolate, acute, slightly recurved, 1-nerved; upper glume 3-4.5 mm long, ovate, obtuse, 3-5-nerved; lowest floret sterile, pur- plish, consisting of only a lemma, this 4.5-6 mm long, ovate, acute, 3-5-nerved; functional florets with lemmas (6-)8-10 mm long, 1.5-2 mm wide (folded width), ovate, obtuse to slightly tridentate, 7-nerved, greenish, glabrous on the back or thinly covered with straggling, glassy hairs 0.2-0.3 mm long, the margins with short, spreading cilia; paleas 7-9 mm long, 1.5 mm wide between the ciliolate keels, nearly as long as but still concealed by the lemma, slightly notched at the apex; rachilla inter- nodes 2-3 mm long, ca. 0.5 mm wide; lodicules 3, 0.9-1 mm long, spatulate, hyaline, several-nerved, short-pilose at the apex; stamens 3, the anthers 2.5- 3.3 mm long, yellow; gynoecium not seen. Fruit not seen.
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Distribution
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Known only from the summit of Apacara-tepui, Chimanta/ Massif, Bolivar, Venezuela.
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Specimen
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VENEZUELA. BOLIVAR: Dist. Piar, Chimantai Massif, altiplanicie en la base meridional de los farallones superiores del Apacara- tepui, frecuente en matorral en el fondo del valle, 5?20'N, 62?12'W, ca. 2,200 m, 30 Jan.-l Feb. 1983 (fl), Huber & Steyermark 7037 (MO, VEN); Dist. Piar, altiplanicie en la base meridional de los farallones superiores del Apacara-tepui, "drier part of savanna bordering large swampy savanna," 5?20'N, 62?12'W, ca. 2,200 m, 30 Jan.-I Feb. 1983 (fl), Steyermark et al. 128370 (MO); Chimanta Massif, secci6n SE del Apacara-tepui, 5?19'N, 62?07'W, ca. 2,150 m, 6-9 Feb. 1984 (st), Huber, Colella & Vareschi 8905 (MO, US).
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Note
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Aulonemia Goudot (Bambuseae: Arthrostylidiinae) is a genus of about 30 described and several undescribed species that ranges from southern Mex- ico and northern South America to Bolivia and south- ern Brazil, at 500 to 3,500 m. It is usually char- acterized by a branching pattern with one large branch dominant at each midculm node; foliage leaves with prominent oral setae and broad, deflexed blades; and open panicles of slender spikelets. Both A. chi- mantaensis and the following species (A. jauaensis) appear to be distinctive within the genus because of their very long spikelets with contrasting purple glumes and numerous, greenish, densely imbricate florets. Table 1 summarizes the differences between the two new species. Two other species of Aulonemia have previously been described from the Guayana Highlands: A. defiexa (N. E. Brown) McClure (Mt. Roraima, Ilu- tepui) and A. steyermarkii (McClure) McClure (Ptari- tepui, Ilu-tepui, and Mt. Roraima). Both differ from A. chimantaensis and A. jauaensis in their smaller, fewer and more loosely flowered, purple spikelets less than 2 cm long. Also, sterile collections of at least four more species of Aulonemia from the Gua- yana Highlands have been examined, but all have distinctive vegetative features that make them unlikely to be closely related to A. chimantaensis and A. jauaensis.
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