Parahyparrhenia siamensis

HABIT Perennial; caespitose. Culms erect; 50 cm long. Leaf-sheaths pilose. Ligule a fringe of hairs; 0.2 mm long. Leaf-blades involute; 5–12 cm long; 1–1.5 mm wide. Leaf-blade surface pilose; hairy on both sides.

INFLORESCENCE Inflorescence composed of racemes; subtended by a spatheole. Spatheole linear; 9–11 cm long; herbaceous.

Racemes 1–2; single, or paired; 4–5 cm long; bearing few fertile spikelets; bearing 4–7 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes filiform. Rhachis internode tip oblique; flat. Raceme-bases filiform; subequal; 7 mm long; glabrous.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; ciliate.

STERILE SPIKELETS Basal sterile spikelets absent.

Companion sterile spikelets well-developed; male; linear; 5–6 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet callus oblong (0.5mm); obtuse. Companion sterile spikelet glumes coriaceous; sulcate; pilose (above); awned; one glume awned (upper); with 2–3 mm long awn. Companion sterile spikelet lemmas 2; enclosed by glumes; 1-awned; with 3 mm long awn.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 8–9.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 2–3 mm long; pilose; base pungent; attached obliquely. Spikelet callus hairs white.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume elliptic; 1 length of spikelet; coriaceous; without keels; 6 -veined. Lower glume surface with a longitudinal median groove; pilose; hairy above. Lower glume margins ciliate. Lower glume apex mucronate; 2 -awned (mucros). Lower glume awn 1.5 mm long. Upper glume elliptic; coriaceous; 5 -veined. Upper glume margins ciliate. Upper glume awned. Upper glume awn 6–9 mm long.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 2.5–3.5 mm long; hyaline. Fertile lemma oblong; 3 mm long; hyaline; without keel. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 40–50 mm long overall; with twisted column. Column of lemma awn hispidulous; hairy on the spiral. Palea absent or minute.

FLOWER Anthers 3; 4 mm long.

DISTRIBUTION Asia-tropical: Indo-China.

NOTES Andropogoneae. WDC.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.