Microstegium steenisii Jansen

Chen, H., Veldkamp, J. - F. & Kuoh, C. - S., 2012, Taxonomic revision of Microstegium s. str. Andropogoneae, Poaceae), Blumea 57 (2), pp. 160-189 : 180-182

14. Microstegium steenisii Jansen — Fig. 12 ; Map 11

Microstegium steenisii Jansen (1953) 306. — Type: Van Steenis 4320 (holo BO; L).

Annuals, mat-forming. Culms geniculately ascending, of moderate stature, 50–80 cm long, rooting from the lower nodes. Nodes pubescent. Sheaths glabrous, outer margin glabrous, oral hairs bearded. Ligule a ciliolate membrane, 0.5–0.7 mm long. Blades lanceolate, 4–5 cm by 6–8 mm wide, firm, base attenuate to slightly rounded, pseudopetiole absent, margins scabrous, apex acute to acuminate, glabrous to moderately hairy on both sides with tubercle-based hairs. Panicles c. 3 cm long, common axis c. 0.5 cm long. Racemes 2–4, digitate, ascending, straight, 4–5 cm long. Rachis fragile, semiterete, margins ciliate, internodes linear, 1–1.5 mm long. Sessile spikelets without a short stalk, deciduous with the adjacent joint and pedicel, lanceolate, c. 5 mm long, callus setose. Lower glume lanceolate, coriaceous, midrib glabrous, dorsally concave, smooth, glabrous, margins setose, apex acute, entire. Upper glume lanceolate, back acute, glabrous or pilose, midrib glabrous, hairy near the base, apex entire, acute, muticous or mucro c. 0.8 mm long. Lower florets well-developed, paleate, or barren, epaleate. Lower lemma lanceolate, c. 4.5 mm long, muticous. Upper lemma oblong, 3–4 mm long, without veins, glabrous, apex incised to 0.25th of the lemma length, awned from a sinus, awn flexuous, column absent, 10–15 mm long. Upper palea oblong, c. 2.3 mm long, c. 0.33th times as long as the lemma, membranous, apex entire. Anthers 3, c. 1.5 mm long. Pedicels linear, flattened, c. 2.5 mm long, margins pubescent. Pedicelled spikelets subequal to the sessile ones. Distribution — Malesia: Java (Papandayan).

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Habitat — Mountains, c. 2040 m altitude.

Note — Known only from the type specimen.

Figures

Fig. 12 Microstegium steenisii Jansen. a. Habit; b. joint of leaf sheath and leaf blade; c. spikelets; d. lower glume; e. upper glume; f. lower lemma; g. upper lemma with long flexuous awn; h. upper palea; i. pistil; j. stamens (all: van Steenis 4320, L).