Panicum crystallinum Judz. & Voronts.

Vorontsova, Maria S., 2018, Revision of the group previously known as Panicum L. (Poaceae: Panicoideae) in Madagascar, Candollea 73 (2), pp. 143-186 : 156-158

8. Panicum crystallinum Judz. & Voronts. in Kew Bull. 69–9511: 4. 2014.

Holotypus: MADAGASCAR. Prov. Antananarivo: Antongona , II.1963, Bosser 17188 ( P [ P00524470 ]!; isotype: P [ P02309315 , P02309316 ]!) .

Delicate annual, semi-prostrate, to 15 cm tall, the culms glabrous. Leaf sheaths glabrous with some cilia at the apex and on the margins. Ligule a lacerate ciliolate membrane. Leaf blades ovate, flat, membranous, 1.5–2.0 × 0.3–0.45 cm, drying yellow-green, loosely hirsute on both sides. Panicles terminal and axillary, partly or fully exserted on a peduncle to 1 cm long, 2–4 cm long, diffuse, the branching distichous or in threes, the branches filiform, partly divergent at maturity, glabrous or with a few white cilia, the pedicels 1–6 mm long. Spikelets ovate to oblong, apically rounded, 0.9–1.1(–1.3) mm long, almost white, never gaping open. Lower glume a nerveless vestige of variable shape. Upper glume as long as the spikelet, translucent, 3-veined, with pronounced bulbous pickle hairs between the veins. Lower floret barren, without a significant palea. Lower lemma translucent, 3–5-veined, with pronounced bulbous pickle hairs between the veins. Upper lemma smooth, shiny, pale.

Distribution and ecology. – Endemic to Madagascar, wet forest understory shade and rocky places on the High Plateau near Antananarivo ( Fig. 2B ).

Notes. – Similar to P. manongarivense A. Camus but with translucent, crystal-like, bulbous-based prickle hairs on the upper glume and lower lemma (vs smaller prickle hairs) and without auricles (vs brown membranous auricles 1–1.5 mm long on mature leaves). Also similar to P. mitopus but spikelets 0.9–1.1(–1.3) mm long (vs 1.1–1.7 mm long).

This species is illustrated in VORONTSOVA (2014: Fig. 1 ).

Additional material examined. – MADAGASCAR. Prov. Antananarivo: Angavokely, V.1961, Bosser 15289 ( P [ P00524460 , P02382370 ]) .

Figures

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).

Fig. 1. – A. Adenochloa hymeniochila (Nees) Zuloaga; B. Panicum andringitrense A. Camus; C. Panicum brevifolium L.; D. Panicum cinctum Hack. [A: Vorontsova et al. 602; B: Vorontsova et al. 1292; C: Unvouchered photo, Andasibe-Mantadia National Park, Madagascar; D: Rakotoarisoa & Randrianavosoa SNGF 2920] [Photos: A–C: M.S. Vorontsova; D: S. Rakotoarisoa]