Acroceras zizanioides

HABIT Perennial. Culms decumbent (from a prostrate base); 30–100 cm long; 1–2.5 mm diam.; 10–20 -noded; rooting from lower nodes. Lateral branches sparse. Leaves cauline. Leaf-sheaths wider than blade at the collar; outer margin hairy. Ligule an eciliate membrane; 0.5 mm long; truncate. Collar pilose. Leaf-blade base broadly rounded. Leaf-blades lanceolate; 4–15 cm long; 6–26 mm wide. Leaf-blade venation with obscure cross veins. Leaf-blade surface ribbed; glabrous. Leaf-blade margins cartilaginous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 3–10; borne along a central axis; unilateral; 4–12 cm long; secondarily branched. Central inflorescence axis 8–20 cm long. Rhachis angular. Spikelet packing lax; irregular.

Spikelets ascending; in pairs. Fertile spikelets pedicelled; 2 in the cluster. Pedicels linear; angular; unequal; 1–6 mm long.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; subterete; 4.5–6.5 mm long; 1.5–2.5 mm wide; falling entire. Spikelet callus glabrous; base truncate.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 0.5–0.8 length of spikelet; herbaceous; without keels; 3 -veined. Lower glume apex acute. Upper glume ovate; 4–6 mm long; herbaceous; 5 -veined. Upper glume apex laterally pinched.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret similar to upper glume; ovate; 1 length of fertile lemma; 1 length of spikelet; herbaceous; 5 -veined; laterally pinched at apex. Palea of lower sterile floret hyaline. Fertile lemma elliptic; dorsally compressed; lanceolate in profile; 4–6 mm long; indurate; pallid; 5 -veined. Lemma surface striate; with distinct germination flap. Lemma margins involute. Lemma apex apiculate; with a little green crest. Palea reflexed at apex; elliptic; involute; 1 length of lemma; indurate; 2 -veined; without keels. Palea apex acute.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 2 mm long. Stigmas 2.

FRUIT Disseminule comprising a spikelet.

DISTRIBUTION Africa: west tropical, west-central tropical, northeast tropical, east tropical, and southern tropical. Asia-tropical: India, Indo-China, and Papuasia. North America: Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Paniceae. FTEA.

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