Iseilema membranaceum

HABIT Annual; caespitose. Culms erect, or geniculately ascending; 5–40(–90) cm long. Leaf-sheaths keeled. Ligule a ciliolate membrane. Leaf-blades flat, or conduplicate; 2–20 cm long; 2–5 mm wide.

INFLORESCENCE Synflorescence compound; linear; 10–18 cm long. Inflorescence composed of racemes; terminal and axillary; deciduous as a whole; subtended by a spatheole; enclosed. Spatheole elliptic; 0.8–1.2 cm long; herbaceous; without tubercles.

Racemes 1; single; oblong; 0.5–0.7 cm long; bearing few fertile spikelets; bearing 1 fertile spikelets on each. Rhachis hairs mainly at internode tip; 1–2 mm long. Rhachis internodes linear; 0.5–1 mm long. Raceme-bases brief (truncate); glabrous, or pilose; with 2 mm long hairs.

Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels filiform; 2.5–3 mm long; scabrous; glabrous.

STERILE SPIKELETS Basal sterile spikelets well-developed; 4 in number; forming an involucre about the fertile; with both pairs arising at about the same level; pedicelled; deciduous with the fertile. Basal sterile spikelet pedicels 1.5–2 mm long. Basal sterile spikelets barren, or male; oblong; 3–4 mm long; smaller than fertile. Basal sterile spikelet glumes coriaceous; scaberulous.

Companion sterile spikelets well-developed; containing empty lemmas, or male; elliptic, or ovate; 2–3.5 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes cartilaginous; 7–9 -veined; scaberulous; glabrous; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 5–6 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes dissimilar; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; without keels; keel-less except near apex; 8 -veined. Lower glume surface asperulous. Lower glume apex entire, or dentate; 2 -fid; truncate. Upper glume lanceolate; 1 length of spikelet; coriaceous; 3 -veined. Upper glume apex acuminate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 2–3 mm long; hyaline; 0 -veined; without midvein; without lateral veins. Fertile florets female. Fertile lemma linear; 2.5–3.5 mm long; membranous; 1 -veined. Lemma apex entire; muticous, or awned; 1 -awned. Principal lemma awn straight, or geniculate; 0–15 mm long overall; without a column, or with twisted column. Column of lemma awn glabrous. Palea absent or minute.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. Vickery.

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