GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Iseilema convexum

HABIT Annual; caespitose; clumped loosely. Culms erect, or geniculately ascending; 30–70 cm long; 2–3 -noded. Lateral branches lacking, or sparse. Leaf-sheaths keeled. Ligule a ciliolate membrane; 0.5 mm long. Leaf-blades conduplicate; 9–18 cm long; 3–5.5 mm wide. Leaf-blade surface scaberulous; rough adaxially. Leaf-blade margins scabrous. Leaf-blade apex acute.

INFLORESCENCE Synflorescence compound; linear; 25–35 cm long. Inflorescence composed of racemes; terminal and axillary; deciduous as a whole; subtended by a spatheole; enclosed. Spatheole elliptic; 1–1.6 cm long; chartaceous; without tubercles. Peduncle 0.4–0.5 cm long; smooth, or scaberulous above.

Racemes 1; single; oblong; 0.6–0.8 cm long; bearing few fertile spikelets; bearing 1 fertile spikelets on each. Rhachis internodes linear; 0.8 mm long. Raceme-bases brief (truncate); pilose; with 2–2.5 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; 2.5–3 mm long; puberulous.

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; 1–1.5 mm long. Basal sterile spikelets barren, or male; oblong; 4–5 mm long; smaller than fertile. Basal sterile spikelet glumes cartilaginous; pubescent.

Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate, or elliptic; 3–4 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes membranous; 9 -veined; pubescent; 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; 5.5–6.5 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; 8–9 -veined. Lower glume surface flat, or concave; pubescent; hairy generally. Lower glume apex emarginate. Upper glume lanceolate; 1 length of spikelet; coriaceous; 3 -veined. Upper glume surface pubescent; hairy below. Upper glume apex acuminate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret elliptic; 2.5–3 mm long; hyaline; 0 -veined; without midvein; without lateral veins; lobed; 2 -fid. Fertile florets female. Fertile lemma linear; 3 mm long; membranous; 1 -veined. Lemma apex lobed; 2 -fid; incised 0.33 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 16–20 mm long overall; with twisted column. Column of lemma awn 8–10 mm long; glabrous. Palea absent or minute.

FLOWER Anthers 3; 1.5 mm long.

FRUIT Caryopsis obovoid; 2.5 mm long.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. CEH.

ADDITIONAL CHARACTERS Lower glume of basal spikelets strongly convex.

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