Iseilema windersii

HABIT Annual; culms solitary, or caespitose. Culms erect; 20–40 cm long; 1–2 -noded. Lateral branches lacking, or sparse. Leaf-sheaths keeled; smooth. Ligule a ciliolate membrane; 1–1.5 mm long. Leaf-blades conduplicate; 8–16 cm long; 3–6 mm wide; glaucous. Leaf-blade surface smooth, or scaberulous; rough adaxially. Leaf-blade margins scaberulous. Leaf-blade apex acute.

INFLORESCENCE Synflorescence compound; linear; 6–18 cm long. Inflorescence composed of racemes; terminal and axillary; deciduous as a whole; subtended by a spatheole; enclosed. Spatheole lanceolate, or elliptic; 1–2 cm long; membranous; brown; tuberculate (on midnerve). Peduncle 0.4–0.5 cm long; pubescent above.

Racemes 1; single; oblong; 0.8–1 cm long; bearing few fertile spikelets; bearing 1 fertile spikelets on each. Rhachis glabrous on surface. Rhachis internodes linear; 0.8 mm long. Raceme-bases brief (truncate); pilose; with 2–3 mm long hairs.

Spikelets in threes (basal paired). Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels filiform; 3–3.5 mm long; pubescent.

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 oblong; 1.5–2 mm long. Basal sterile spikelets male; 3–4 mm long; smaller than fertile. Basal sterile spikelet glumes cartilaginous; pubescent; smooth on margins, or scabrous on margins.

Companion sterile spikelets well-developed; male; elliptic; 4–5 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes membranous; 7–11 -veined; puberulous; acute; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; acuminate; 7–8 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes dissimilar; firmer than fertile lemma. Lower glume elliptic; 1 length of spikelet; coriaceous; without keels; keel-less except near apex; 8–10 -veined. Lower glume surface flat. Lower glume margins ciliolate. Lower glume apex emarginate, or truncate. Upper glume lanceolate; 1 length of spikelet; coriaceous; 3 -veined. Upper glume primary vein ciliolate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 3–4 mm long; hyaline; 1 -veined; without lateral veins. Fertile florets female. Fertile lemma linear; 4–5 mm long; membranous; 1 -veined. Lemma apex lobed; 2 -fid; with filiform lobes; incised 0.25 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 18–33 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Anthers 3; 1.5–2.2 mm long.

FRUIT Caryopsis oblong, or obovoid; 2.5–3.5 mm long.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. CEH.

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