Panicum inconspicuum Voronts.

Vorontsova, Maria S., 2018, Revision of the group previously known as Panicum L. (Poaceae: Panicoideae) in Madagascar, Candollea 73 (2), pp. 143-186 : 164

16. Panicum inconspicuum Voronts. in Kew Bull. 69–9511: 6. 2014.

Holotypus: MADAGASCAR. Prov. Toliara: Onilahy valley , the seven lakes , III.1960, Bosser 14595 ( TAN!; isotype: P [ P02307405 ]!) .

Delicate annual, ascending, rooting at lower nodes, 15–30 cm tall, the culms glabrous. Leaf sheaths largey glabrous with ciliate edges. Ligule a lacerate membrane. Leaf blades elliptic, flat, membranous, 1.5–6 × 0.5–1 cm, drying yellow-green, glabrous or with sparse bulbous-based cilia on both sides. Panicles terminal, partly or fully exserted on a peduncle 5–7 cm long, 4–10 cm long, ovate, side branches single, the branches divergent at maturity, scabrous, the spikelets usually paired, the pedicels 0.5–7 mm long. Spikelets elliptic, apically rounded, 1.2–1.3 mm long, pale green, never gaping open. Lower glume 1/3–½ as long as the spikelet, obtuse to acute, 3-veined, glabrous becoming pubescent with curved glassy trichomes at maturity. Upper glume as long as the spikelet, membranous, 5-veined, glabrous becoming pubescent with curved glassy trichomes at maturity. Lower floret barren, without a significant palea. Lower lemma translucent, 3–5-veined, glabrous becoming pubescent with curved glassy trichomes at maturity. Upper lemma, apically apiculate, smooth, shiny, pale brown.

Distribution and ecology. – Endemic to southwestern Madagascar, understory of dry forest on limestone, 50–350 m elevation ( Fig. 8B ).

Notes. – Previously overlooked likely due to its superficial resemblance to the common P. brevifolium . Differs from P. brevifolium by its lower glume 1/3–½ as long as the spikelet (vs lower glume as long as the spikelet in P. brevifolium ) and elliptic leaves (vs ovate in P. brevifolium ).

This species is illustrated in VORONTSOVA (2014: Fig. 2 ).

Additional material examined. – MADAGASCAR. Prov. Toliara: les 7 lacs , rte Tongobory , 16.V.1951, Bosser 6 bis ( P [ P02307404 ]) ; 50 km de Tulear, rte de Sakaraha , III.1960, Bosser 14065 ( P [ P02726877 ]) ; ibid. loco, III.1960, Bosser 14066b ( P [ P02726878 ]) ; Beomby , plateau Mahafaly , III.1960, Bosser 14167 ( P [ P02726875 ]) ; forêt du Zombitsy , III.1964, Bosser 19362 ( P [ P06795981 ]) ; Fiherenana aux env. de Manera , V.1933, Perrier de la Bâthie 19215 ( P [ P02307334 ]) .

Figures

Fig. 8. – Distribution maps. A. Panicum cupressifolium A. Camus (stars), P. danguyi A. Camus (triangles), P. dregeanum Nees (circles) and P. flacourtii A. Camus (squares); B. Panicum humbertii A. Camus (stars), P. humile Nees ex Steud. (triangles), P. ibitense A. Camus (circles) and P. inconspicuum Voronts. (squares).

Fig. 2. – Distribution maps. A. Adenochloa hymeniochila (Nees) Zuloaga (stars), Panicum ambositrense A. Camus (triangles), P. andringitrense A. Camus (circles) and P. ankarense A. Camus (squares); B. Panicum brevifolium L. (stars), P. capuronii A. Camus (triangle), P. cinctum Hack. (circles) and P. crystalinum Judz. & Voronts. (squares).