GrassBase - The Online World Grass Flora

Descriptions

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

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

Pereilema

HABIT Annual. Culms decumbent; 15–50.62–80 cm long; without nodal roots (1), or rooting from lower nodes. Lateral branches lacking (1/1). Leaf-sheath auricles falcate. Ligule an eciliate membrane.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted (2), or spiciform (2). Panicle axis bearing persistent branches (3), or deciduous spikelet clusters (1).

Spikelets subtended by an involucre. Fertile spikelets pedicelled; 1–2 in the cluster (2), or 3 in the cluster (3), or 4 in the cluster (2). Companion sterile spikelets sessile; 2–3 in the cluster (3), or 4–12 in the cluster (1). Involucre composed of imperfect spikelets. Pedicels oblong.

STERILE SPIKELETS Companion sterile spikelets represented by awns; persistent (3), or deciduous with the fertile (1).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate (3), or oblong (1); laterally compressed (3), or subterete (1); 1–1.93–3 mm long; falling entire (1), or breaking up at maturity (3); deciduous with accessory branch structures (1/1); disarticulating below each fertile floret (3/3). Floret callus pilose (2/3), or bearded (1/3).

GLUMES Glumes persistent (3/3); shorter than spikelet; thinner than fertile lemma (3), or similar to fertile lemma in texture (1). Lower glume subulate (1), or elliptic (1), or oblong (1), or ovate (2); 1 length of upper glume; membranous (3/3); 1-keeled (3/3); 1 -veined (3/3). Lower glume lateral veins absent (3), or distinct (1). Lower glume surface without pits; glabrous (3), or pilose (1). Lower glume apex emarginate (1/3), or acute (2/3); awned (3/3). Upper glume subulate (1), or lanceolate (2), or oblong (1); 0.33–0.605–0.66 length of adjacent fertile lemma; membranous (3/3); 1-keeled (3/3); 1 -veined (3/3). Upper glume surface glabrous (3), or pilose (1). Upper glume apex emarginate (1/3), or acute (2/3); awned (3/3); 1 -awned (3/3).

FLORETS Fertile lemma lanceolate (2), or ovate (2); membranous (1), or cartilaginous (3); keeled; wingless; 3 -veined. Lemma surface smooth (2), or scabrous (2); unwrinkled; without grooves; glabrous (3), or pubescent (1). Lemma apex entire (3), or dentate (1); 2 -fid (1/1); acuminate (3/3); awned; 1 -awned. Principal lemma awn straight (2), or flexuous (2). Palea 1–1.012–1.05 length of lemma; 2 -veined (1/1). Palea keels separated (2), or approximate (2); smooth (3), or scaberulous (1). Palea apex dentate (1/1); muticous (2), or with excurrent keel veins (2).

FLOWER Anthers 2 (1/3), or 3 (2/3).

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America (3), or South America.

Please cite this publication as detailed in How to Cite Version: 27th January 2014.