Merostachys burmanii (Poaceae: Bambusoideae: Bambuseae), a New Species from Brazil

Abstract

Merostachys burmannii, a new species from Brazil, is described and illustrated. The South American genus Merostachys (Poaceae: Bambusoideae: Bambuseae) comprises approximately 40 species and has a center of diversity in Brazil. The first attempt to recognize and order the species in this genus was made by McClure (1973), who listed ca. 25 species. During fieldwork and herbarium studies aimed at completing a revision of this genus, several new species have been discovered, one of which is described and illustrated here. Taxonomic understanding of genus Merostachys has grown slowly. This is due to the long interval between flowering cycles-some 30-33 years-and to the difficulties in bringing together the rare collections. Because of long-standing diversity of opinion regarding interpretation of the spikelet morphology in the genus, a well-founded and adequate terminology for bamboo descriptions is under investigation. For now, the most suitable terms from standard grass taxonomy are used. Merostachys burmanii Sendulsky, sp. nov. TYPE: Brazil. Sao Paulo, Jardim Botanico, 25 Mar. 1944 (fl), Kuhlmann s.n. (holotype, SP sheet no. 79757; isotype, US sheet no 2678539). Figure 1. Culmi praeter apices flexuosos erecti, 10-15 m alti, ca. 4 cm diametro; internodiis fistulosis, luteis vel fuscoviridibus plerumque laevibus, nonnumquam scabris, aculeis retrorsis, acutisque; nodis prominentibus, fuscis; culmo sub nodo pilis albidis adpressis interdum cera mixtis vestito. Folia culmi vagina ca. 30 cm longa, 10 cm lata, ad apicem asymmetrica, rotundata, fimbriata, setis ca. 0.5 mm longis; lamina reflexa, ca. 17 cm longa, 18-20 mm lata, acuminatissima. Rami verticillati, in complemento 100-130, usque ad 65 cm longi, 1-2 mm diametro, teretes, laeves, glabri. Folia ramorum in complemento 79; vagina glabra, setis oralibus caducis, 2-3 mm longis; lamina 15-17 cm longa, 2-3 cm lata, lineari-lanceolata, glabra, apice acuminata. Inflorescentia spiciformis, non pectinata, 8-11 cm longa, erecta, rami ad apicem disposita; spiculis saepe deflexis, plerumque binatis, interdum solitariis, rarissime ternatis. Caryopsis oblonga, ovoidea, asymmetrica, rostrata, luteo-castanea, laevis, 6-7 mm longa, 2-2.5 mm lata. Culms 10-15 m long, ca. 4 cm diam., erect except at flexuous tips, the slender young culms strongly and retrorsely scabrous. Internodes 38-40 cm long, terete, fistulose, dark yellow or greenish, mostly smooth and shiny, though otherwise smooth culms may display strongly scabrous areas with retrorse, sharp, hooklike prickle hairs; culm walls weak, 1-3 mm thick. Nodes salient, dark, with a layer of velvety whitish hairs below, hairs and wax sometimes mixed together. Culm leaves caducous: sheaths ca. 28-30 cm long, 10 cm wide, rounded and asymmetrical at the summit, fringed at the apex only with fine hairs, these ca. 0.5 mm long; margins smooth and shiny along the adaxial surface, membranous, without cilia; abaxial surface nearly glabrous at the base, retrorsely scabrous at the apex, the adaxial surface shiny; inner ligule a fine membrane, ciliolate on margin, 1-2 mm long, wider in the middle; outer ligule a salient rim; blades reflexed, ca. 17 cm long, 18-20 mm wide, strongly nerved, gradually attenuate to a fine point. Branch complement with 100-130 branches (200-300 fide Soderstrom), these up to 50-65 cm long, 1-2 mm thick, yellowish, smooth, glabrous, shiny, the internodes ca. 17 cm long, 2-3(-5)-noded before the leaves, nodes usually black, sometimes dark yellow, prominent. Foliage leaves 7-9 per complement, the lower well developed, distant below; sheaths tight, glabrous, adaxial surface smooth, densely dark-spotted; oral setae caducous, 2-3 mm long, whitish, diminishing in size downward along the upper margin of the sheath; inner ligule arcuate, ca. 1 mm long, coriaceous, minutely ciliolate on the margin; outer ligule a salient, glabrous rim; pseudopetiole flat, dark, glabrous, 4 mm long; blades 15-17 cm long, 2-3 cm wide, linear-lanceolate, asymmetrical, gradually attenuate toward the apex, glabrous on both surfaces, the adaxial surface sometimes with 2-3 marginal nerves on one side with rows of very fine prickle hairs, the margins and the apex finely scabrous. Inflorescence terminal on a leafy branch, spicate, not pectinate, erect, 8-11 cm long, ca. 2 cm wide, bearing secund, mostly deflexed, laterally outspread, paired spikelets. Peduncle of the inflorescence densely and retrorsely scabrid. Rachis sinuous, longitudinally NOVON 2: 111-113. 1992. This content downloaded from 157.55.39.35 on Wed, 31 Aug 2016 04:52:38 UTC All use subject to http://about.jstor.org/terms