Microstegium petiolare (Trin.) Bor

Chen, H., Veldkamp, J. - F. & Kuoh, C. - S., 2012, Taxonomic revision of Microstegium s. str. Andropogoneae, Poaceae), Blumea 57 (2), pp. 160-189 : 176

10. Microstegium petiolare (Trin.) Bor — Fig. 8 ; Map 9

Microstegium petiolare (Trin.) Bor (1938) 87. — Spodiopogon petiolaris Trin. (1832) 301. — Andropogon petiolaris (Trin.) Steud. (1854b) 398. — [ Andropogon petiolatus Dalzell (1861) 303, orth. var.]. — Ischaemum petiolare (Trin.) Hack. (1889) 238. — Type: Wallich in Herb. Hornemann (holo C; in Herb. Trin. 66.1, LE, a beautiful drawing and fragments, microfiche IDC BT-16/1). Bor (1952) and Sur (1985) have Wallich 8807 (BM, CAL, K, microfiche IDC 7394), Roberty (1960) cited 8807­A (G).

Pollinia lehmannii Arn. & Nees (preprint of 1843: 1841) 54; (1843) 186 (‘ lehmanni ’). — Spodiopogon lehmannii (Arn. & Nees) Griseb. (1868) 91. — Type: Not indicated, presumably Herb. Lehmann s.n. (? holo S).

Microstegium yunnanense R.J.Yang (1984) 221. — Type: R.J. Yang & Y.G. Han 77025 (holo SYAU) .

Perennials, mat-forming. Culms rambling or scandent, reed-like or robust, 60–100(–400) cm long, rooting from the lower nodes. Nodes pubescent. Sheaths glabrous, outer margin glabrous or hairy, oral hairs absent. Ligule a glabrous membrane, 3–6 mm long. Blades lanceolate or elliptic, 5–30 cm long, 10–25 mm wide, firm, base attenuate to slightly rounded, base pseudopetiole present, margins scabrous, apex acuminate, gradually attenuate, pilose, sparsely or moderately hairy on both sides, without tubercle-based hairs. Panicles 6 –16 cm long, common axis 1.5–5 cm long. Racemes 8–20, digitate, ascending, straight, 6–14 cm long. Rachis fragile, semiterete, margins ciliate, internodes linear, internodes 3–4.5 mm long. Sessile spikelets without a short stalk, deciduous with the adjacent joint and pedicel, elliptic, 4.5–5 mm long, spikelet callus puberulous. Lower glume elliptic, coriaceous, midrib glabrous, dorsally concave, scaberulous, rough all over, glabrous, margins ciliate, apex acute, entire. Upper glume elliptic, back acute, glabrous, midrib glabrous, apex entire, acute, muticous. Lower florets present, well-developed, paleate, male or barren, with palea. Lower lemma present, 4–5 mm long, muticous. Upper lemma oblong, 3–4 mm long, without veins, glabrous, apex incised, incised to 0.5–0.6th of the lemma length, apex awned, awn from a sinus, geniculate, column twisted, (incl. column) 6–8 mm long. Upper palea absent or minute. Anthers 3, 2.5–3 mm long. Pedicels linear, semiterete, 3.5–4 mm long, margins pubescent. Pedicelled spikelets subequal to the sessile ones.

Distribution — India (Meghalaya, Orissa), Nepal, Sikkim, Thailand (Chiangmai, Loei), Burma (Kachin, Mandalay), China (Yunnan).

Habitat — Grasslands, thickets, along paths, 1525–2100 m altitude.

Uses — Forage.

Collector’s notes — Culms erect, sometimes scrambling, c. 1.2 m tall.

Notes — 1. The species has been illustrated by Chen & Phillips (2007).

2. The collection Evrard 1777 (L, P) from S Vietnam (Dalat) is best placed here, although it differs in some respects. It is a new record for the country. – Ligule 1.5 mm long. Racemes 1–7. Lower glume apex emarginate and more or less 2-winged. Anthers c. 1.7 mm

long. Pedicels 2.5–3 mm long............ Evrard 1777 – Ligule 3–6 mm long, Blades Racemes 8–20. Lower glume apex acute. Anthers 2.5–3 mm long. Pedicels 3.5–4 mm

long................................. M. petiolare

Figures

Map 9 Distribution of Microstegium petiolare (Trin.) Bor. (★) and M. rufispicum (Steud.) A.Camus (●).

Fig. 8 Microstegium petiolare (Trin.) Bor.a.Habit; b. spikelets;c. lower glume; d. upper glume;e. lower lemma;f. upper lemma with awn; g. upper palea;h. joint of leaf sheath and leaf blade (all: Polunin, Sykes & Williams 5760, K).