A New Species of Paspalum (Gramineae) from Bolivia

Abstract

Summary. A new species, Paspalum reticulinerve Renvoize, is described from Bolivia and compared with 6 other related species of section Pectinata Chase ex Rodriguez. The genus Paspalum with 330 species, the majority of them in the New World, is the fourth largest in the Gramineae, after Poa (500), Panicum (470) and Festuca (450). Paspalum species are readily recognized by their typically ovate, orbicular or elliptic, strongly plano-convex 2-flowered spikelets arranged in 2 or 4 dense rows on one side of a broad or narrow rachis. The new species described here is somewhat atypical and belongs to Section Pectinata Chase ex Rodriquez in which the spikelets are strongly dorsiventrally flattened, imbricate, and lanceolate in shape, and the upper glume is usually winged and cordate. The new species differs from all the other related species most obviously in its ciliate rachis. P. reticulinerve Renvoize sp. nov. P. aspidioti Trin. affinis sed planta omnis villosa, laminis angustioribus, racemis exsertis, rachidi ciliata, spiculis brevioribus differt. Typus: Bolivia, Solomon 17003 (holotypus LPB; isotypi K, MO). Gramen perenne, caespitosum, villosum; culmis erectis 120 cm altis. Foliorum basalium vaginae papyraceae; laminae lineares 20-30 cm x 3-5 mm planae attenuatae, basi rectae. Racemi 2(-3) terminales exserti conjugati 9 cm longi; rhaches lunares, 1 mm latae, ciliatae. Spiculae solitariae late lanceolatae, 4 -55 mm longae, dorsiventraliter compressae bifariae imbricatae. Gluma superna lemmatem infera longior et latior, foliaceo-alata, alae reticulato-venosae acutae cordatae 5-nerviae, margines apicalibus ciliolati. Lemma infera coriacea granulatopapillosa, 3 -5 mm longa, alata, alis reticulato-venosis, basi plicatis marginibus apicalibus ciliolatis. Anthoecium hermaphroditum ellipticum 3 mm longum. Caespitose, villous perennial with erect culms 120 cm high. Basal leaf-sheaths papery; blades linear, 20-30 cm x 3-5 mm, straight at the base, flat, tapering at the apex. Racemes 2(-3), exserted, conjugate, 9 cm long; rachis crescentic, 1 mm wide, ciliate. Spikelets usually solitary, occasionally paired imbricate, arranged in two rows, broadly lanceolate, 4"-5-5 mm long, dorsi-ventrally compressed. Upper glume longer and broader than the lower lemma, foliaceously winged, the wings reticulately nerved, cordate, 5-nerved, acute, the margins ciliolate near the apex. Lower lemma coriaceous, granular-papillose, 3-5 mm long, winged, the wings reticulately nerved, plicate at the base, the margins ciliolate towards the apex. Upper floret hermaphrodite, elliptic, 3 mm long. Fig. 1A-G.