Ichnanthus tenuis

HABIT Annual; mat forming. Culms rambling; 10–40 cm long; rooting from lower nodes. Culm-internodes distally pubescent, or pilose. Lateral branches ample. Leaf-sheaths pilose; with simple hairs, or tubercle-based hairs. Ligule a ciliate membrane; 1–1.5 mm long. Leaf-blade base broadly rounded; asymmetrical. Leaf-blades linear, or lanceolate, or ovate; 2–7 cm long; 6–15 mm wide. Leaf-blade venation with distinct cross veins. Leaf-blade surface pubescent, or pilose. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle, or composed of racemes; terminal and axillary. Peduncle 6–20 cm long.

Panicle open; ovate; 3–9 cm long. Primary panicle branches 2–7 in number; simple; 2–7 cm long; bearing spikelets almost to the base. Panicle branches flexuous.

Racemes 2–7; borne along a central axis; 2–7 cm long. Central inflorescence axis 1.5–6 cm long. Spikelet packing lax; irregular.

Spikelets ascending; in pairs. Fertile spikelets sessile and pedicelled; 2 in the cluster. Pedicels filiform; angular.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 3.5–5 mm long; falling entire; readily shedding fertile florets. Floret callus winged; with apical wings shrivelled to concave scars; these appendages 0.5–1 mm long.

GLUMES Glumes similar; reaching apex of florets; thinner than fertile lemma. Lower glume lanceolate; 0.66–1 length of spikelet; herbaceous; 1-keeled; 3 -veined. Lower glume lateral veins ribbed. Lower glume surface pilose. Lower glume apex attenuate. Upper glume elliptic; 1 length of spikelet; herbaceous; 1-keeled; 5 -veined. Upper glume surface pilose. Upper glume apex setaceously attenuate.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret similar to upper glume; lanceolate; 1 length of spikelet; 1-keeled; 5 -veined; setaceously attenuate. Fertile lemma elliptic, or oblong; dorsally compressed; 1.5–3 mm long; indurate; without keel. Lemma margins involute. Lemma apex obtuse, or acute. Palea involute; indurate.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Paniceae. Stieber.

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