Tristachya

HABIT Annual (1), or perennial (20). Rhizomes absent (15), or short (4), or elongated (2). Culms erect (20), or geniculately ascending (1), or decumbent (1); 20–97.2–270 cm long. Lateral branches lacking (5/6), or sparse (2/6). Ligule a fringe of hairs. Leaf-blades filiform (3), or linear (18); herbaceous (19), or coriaceous (2); stiff (4), or firm (17). Leaf-blade margins cartilaginous (1/1).

INFLORESCENCE Inflorescence a panicle (20), or composed of racemes (1); exserted (20), or embraced at base by subtending leaf (1).

Panicle open (14/19), or contracted (6/19). Primary panicle branches not whorled (20/20), or whorled at lower nodes (1/20).

Racemes single (1/1); bilateral (1/1); bearing few fertile spikelets (1/1); bearing 3–24 fertile spikelets on each (1/1). Rhachis angular (1/1).

Spikelets appressed (1/1); in pairs (3), or in threes (20). Fertile spikelets pedicelled; 2 in the cluster (3), or 3 in the cluster (20); subequal (2/2). Pedicels free (8), or fused to each other (13); filiform (3/3), or linear (1/3).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; of unremarkable solid shape (20), or turbinate (1); laterally compressed; 8–22.92–45 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; pubescent (14/20), or pilose (1/20), or bearded (5/20); acute (1), or pungent.

GLUMES Glumes persistent; shorter than spikelet (3), or reaching apex of florets (1), or exceeding apex of florets (18). Lower glume lanceolate (17), or elliptic (3), or ovate (1); chartaceous (19), or coriaceous (2); without keels; 3 -veined. Lower glume surface smooth, or asperulous (1); without pits; glabrous (14), or pilose (2), or hispidulous (1), or setose (9). Lower glume apex acute (14), or acuminate (6), or attenuate (3), or setaceously attenuate (3). Upper glume lanceolate; chartaceous; without keels; 3 -veined. Upper glume surface glabrous, or setose (1); with tubercle-based hairs (1/1). Upper glume apex entire, or dentate (1); 2 -fid (1/1); obtuse (8/20), or acute (10/20), or acuminate (3/20), or attenuate (1/20).

FLORETS Basal sterile florets male, or barren (1); with palea. Lemma of lower sterile floret lanceolate; chartaceous; 3 -veined (1/20), or 5–7 -veined (19/20); acute (19), or acuminate (3). Fertile lemma elliptic (1), or oblong (20); coriaceous; without keel; wingless; 5 -veined (1/15), or 7 -veined (11/15), or 9 -veined (3/15). Lemma surface unwrinkled; without grooves; glabrous (4), or pubescent (15), or pilose (2); hairy on back (16/17), or in lines (1/17); without hair tufts (18), or with a transverse row of hair tufts (3). Lemma margins involute; interlocking with palea keels. Lemma apex dentate (2), or lobed (19); 2 -fid; incised 0.2–0.2643–0.4 of lemma length; acute (3/4), or setaceously attenuate (1/4); awned; 1 -awned (11), or 3 -awned (10). Principal lemma awn from a sinus; geniculate. Lateral lemma awns shorter than principal (6/6). Palea membranous (20), or coriaceous (1); 2 -veined. Palea keels approximate; unthickened (2), or thickened (19); wingless (13), or winged (8). Palea surface glabrous (18), or pubescent (3).

FLOWER Anthers 3 (20/20). Ovary glabrous (3/14), or pubescent on apex (11/14).

FRUIT Caryopsis with adherent pericarp (20/20); linear (2/2). Hilum linear (2/2).

DISTRIBUTION Africa (17), or North America (3), or South America (2).

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