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.

Pereilema diandrum

HABIT Annual; caespitose. Culms decumbent; 40–80 cm long; 1–2 mm diam.; without nodal roots, or rooting from lower nodes. Culm-internodes scaberulous. Culm-nodes glabrous. Lateral branches lacking. Leaf-sheaths antrorsely scabrous. Leaf-sheath oral hairs ciliate. Leaf-sheath auricles falcate. Ligule an eciliate membrane; 0.7–1 mm long. Leaf-blades 10–20 cm long; 5–8 mm wide. Leaf-blade surface scabrous.

INFLORESCENCE Inflorescence a panicle. Peduncle 3–6 cm long.

Panicle contracted; linear; continuous, or interrupted; 10–20 cm long; 1–2 cm wide; contracted about primary branches. Primary panicle branches appressed; 1–3 cm long; bearing spikelets almost to the base. Panicle axis angular; scabrous.

Spikelets subtended by an involucre. Fertile spikelets pedicelled; 3–4 in the cluster. Companion sterile spikelets sessile; 2–3 in the cluster. Involucre composed of imperfect spikelets; cuneate. Pedicels oblong.

STERILE SPIKELETS Companion sterile spikelets represented by awns; comprising a tuft of awns; 3–5 mm long; persistent. Companion sterile spikelet glumes glabrous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 1.9–2.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pilose. Floret callus hairs 0.5–0.8 mm long.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume elliptic, or ovate; 0.7–1.5 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute; awned; 1 -awned. Lower glume awn 1.5–4 mm long. Upper glume lanceolate; 0.7–1.5 mm long; 0.33–0.66 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute; awned; 1 -awned. Upper glume awn 1.5–4 mm long.

FLORETS Fertile lemma lanceolate; 1.9–2.5 mm long; cartilaginous; keeled; 3 -veined. Lemma surface scabrous. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn straight; 10–24 mm long overall. Palea 1.05 length of lemma. Palea keels approximate. Palea apex dentate; 2 -fid; with excurrent keel veins.

FLOWER Anthers 2; 0.8–1 mm long; purple.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION South America: Mesoamericana.

NOTES Eragrostideae. Pohl 1994.

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