Piresia

HABIT Perennial. Culms erect (1/1), or geniculately ascending (1/1); 7–23.87–50 cm long; wiry. Ligule an eciliate membrane. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades lanceolate (2), or oblong (1), or ovate (1).

INFLORESCENCE Monoecious; with male and female spikelets in the same inflorescence. Synflorescence on the same culm as leaves (1), or on a separate leafless culm. Inflorescence composed of racemes; terminal (2), or terminal and axillary (2).

Racemes single; bearing few fertile spikelets; bearing 2 fertile spikelets on each (3), or 3 fertile spikelets on each (2), or 4–6 fertile spikelets on each (1).

Sexes mixed. Spikelets solitary (1), or in pairs. Fertile spikelets pedicelled; 1 in the cluster. Male spikelets sessile; 1 in a cluster. Pedicels cuneate.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic (3), or ovate (1); dorsally compressed; 4.98–6.335–8 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes deciduous; reaching apex of florets (3), or exceeding apex of florets (1); thinner than fertile lemma. Lower glume elliptic (3), or ovate (1); 1 length of upper glume; herbaceous; without keels; 5 -veined. Lower glume lateral veins without ribs (2), or ribbed (2). Lower glume surface without pits; glabrous (3), or puberulous (1). Lower glume apex acute (2), or acuminate (2). Upper glume elliptic (3), or ovate (1); 1–1.05–1.2 length of adjacent fertile lemma; herbaceous; without keels; 3 -veined (3), or 5 -veined (1). Upper glume lateral veins without ribs (2), or ribbed (2); with cross-veins (2/2). Upper glume surface glabrous (3), or puberulous (1). Upper glume apex acute (2), or acuminate (2).

FLORETS Fertile florets female. Fertile lemma elliptic (3), or ovate (1); indurate; without keel; wingless; 5 -veined. Lemma surface unwrinkled; without grooves; pubescent. Lemma margins exposing palea (3), or covering most of palea (1). Lemma apex truncate (1/1). Palea indurate; 2 -veined.

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp (1/1); ovoid (1/1). Embryo 0.2 length of caryopsis. Hilum linear (1/1); 1 length of caryopsis.

MALE Male spikelets distinct from female; lanceolate. Male spikelet glumes absent. Male spikelet lemma muticous.

DISTRIBUTION South America.

Please cite this publication as detailed in How to Cite Version: 16th November 2012.