Panicum manongarivense A. Camus

Vorontsova, Maria S., 2018, Revision of the group previously known as Panicum L. (Poaceae: Panicoideae) in Madagascar, Candollea 73 (2), pp. 143-186 : 166-168

18. Panicum manongarivense A. Camus in Bull. Soc. Bot. France 72: 707. 1925 ( Fig. 11 ).

Lectotypus (designated here): MADAGASCAR. Prov. Antsiranana: massif de Manongarivo , IV.1909, Perrier de la Bâthie 11091 ( P [ P00450232 ]!; isolectotype: K [ K000244705 ]!, P [ P00450233 ]!, TAN [ TAN000390 ]!) .

Delicate prostrate or ascending annual to 50 cm long, the culms glabrous. Ligule a lacerate ciliolate membrane, c. 0.7 mm long, with brown membranous auricles 1– 1.5 mm long on mature leaves. Leaf blades ovate to lanceolate, membranous, 0.5–4.5 × 0.2–0.8 cm, drying glaucous, glabrous to sparsely hirsute on both sides. Panicles terminal and axillary, pendent, partly exserted with no clear peduncle, 0.5–7 cm long, diffuse, the branching distichous or in threes, the branches filiform, partly divergent at maturity, glabrous or with numerous white cilia exceeding the spikelet, the pedicels 1–6 mm long. Spikelets ovate to oblong, apically rounded, 0.9–1.1 mm long, almost white, never gaping open. Lower glume a nerveless vestige of variable shape. Upper glume ½ to as long as the spikelet, translucent, 3-veined, with small trichomes between the veins or towards the apex. Lower floret barren, without significant palea. Lower lemma translucent, 3–5-veined, with minute trichomes between the veins or towards the apex. Upper lemma smooth, shiny, pale.

Distribution and ecology. – Endemic to Manongarivo and nearby; humid mid-elevation habitats, 500–1500 m ( Fig. 10A ).

Notes. – Close to P. mitopus but spikelets smaller and white.

The lectotype has been chosen from two sheets of original material examined by Camus at P and constitutes the higher quality reproductive material.

Additional material examined. – MADAGASCAR. Prov. Antsiranana: Manongarivo, Antsatrotro E of Ankaramy , 14°05'S 48°23'E, 26.III.1993, Malcomber et al. 2310 ( K [ K000805497 ], P [ P06795304 ]) ; Manongarivo, E de Ankaramy-be , Bekolosy , 14°04'S 48°17'E, IV.1993, Rakotomalaza 21 ( P [ P02373631 ]) ; 10 km SW of Andranomololo, 14°21'34"S 49°22'35"E, IV.2006, Rakotovao et al. 3178 ( P [ P02309332 ]) .

Figures

Fig. 11. – Panicum manongarivense A. Camus. A. Habit; B. Ligule area; C. Panicle branch; D. Spikelet; E. Lower glume; F. Upper glume, dorsal view; G. Upper glume, ventral view; H. Lower lemma, dorsal view; I. Lower lemma apex, enlarged; J. Lower lemma, ventral view; K. Upper floret, lateral view; L. Upper floret, ventral view; M. Upper lemma, dorsal view; N. Upper lemma, ventral view; O. Upper palea, dorsal view; P. Upper palea, ventral view. [Rakotovao et al. 3178, K] [Drawing: Lucy T. Smith]

Fig. 10. – Distribution maps. A. Panicum luridum Hack. (stars), P. manongarivense A. Camus (triangles), P. mitopus K. Schum. (circles) and P. novemnerve Stapf (squares); B. Panicum palackyanum A. Camus (stars), P. perrieri A. Camus (triangles), P. pleianthum Peter (circles) and P. spergulifolium A. Camus (squares).