Iseilema macratherum

HABIT Annual; caespitose. Culms erect, or geniculately ascending; 25–70 cm long. Leaf-sheaths keeled. Ligule a ciliolate membrane. Leaf-blades flat, or conduplicate; 10–25 cm long; 2–6 mm wide.

INFLORESCENCE Synflorescence compound; linear; 5–20 cm long. Inflorescence composed of racemes; terminal and axillary; deciduous as a whole; subtended by a spatheole; enclosed. Spatheole lanceolate, or elliptic; 1–1.6 cm long; herbaceous; without tubercles. Peduncle 0.2–0.35 cm long; disarticulating; disarticulating below uppermost sheaths (raceme eventually disarticulating).

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

Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels filiform; 3.5–4 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 1.5–2 mm long. Basal sterile spikelets barren, or male; elliptic, or oblong; 4–4.5 mm long; smaller than fertile. Basal sterile spikelet glumes membranous; scaberulous.

Companion sterile spikelets well-developed; male; lanceolate; 3–5 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes cartilaginous; 5–7 -veined; glabrous; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 6–7 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; 6–9 -veined. Lower glume apex entire; 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; 3 mm long; hyaline; 0 -veined. Fertile lemma linear; 5 mm long; membranous; 1 -veined. Lemma apex entire; awned; 1 -awned. Principal lemma awn geniculate; 20–30 mm long overall; with twisted column. Column of lemma awn 8–15 mm long; glabrous. Palea absent or minute.

FRUIT Caryopsis with adherent pericarp; oblong; 2.5 mm long.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. CEH.

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