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.

Rhytachne

HABIT Annual (3), or perennial (9). Rhizomes absent (10), or short (2). Culms erect (2/2); slender (2/2); 15–71.23–180 cm long. Lateral branches ample (1/1). Leaf-sheath auricles absent (11), or erect (1). Ligule an eciliate membrane (3), or a ciliolate membrane (9). Leaf-blades filiform (6), or linear (7).

INFLORESCENCE Inflorescence composed of racemes. Peduncle widened at apex (1/1).

Racemes single. Rhachis fragile at the nodes; semiterete. Rhachis internodes columnar (2), or clavate (2), or cuneate (8). Rhachis internode tip transverse; crateriform.

Spikelets squeezed between internode and pedicel (1/1); in pairs. Fertile spikelets sessile (11), or sessile and pedicelled (1); 1 in the cluster (11), or 2 in the cluster (1). Companion sterile spikelets pedicelled (11/11); 1 in the cluster (11/11). Pedicels linear.

STERILE SPIKELETS Companion sterile spikelets absent (1), or represented by barren pedicels (5), or represented by awns (3), or rudimentary (6), or well-developed (2); deciduous with the fertile (10/10). Companion sterile spikelet glumes muticous (7/7).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (3), or elliptic (1), or oblong (6), or ovate (5); dorsally compressed; 2–5.827–9 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous (8), or pubescent (4); base truncate; with central peg; attached transversely.

GLUMES Glumes exceeding apex of florets; firmer than fertile lemma. Lower glume elliptic (1), or oblong (11); chartaceous (1), or coriaceous (11); without keels; wingless (8), or winged on margins (4); 4 -veined (2/9), or 5 -veined (5/9), or 6 -veined (3/9), or 7 -veined (4/9), or 9 -veined (2/9). Lower glume lateral veins without ribs (10), or ribbed (2). Lower glume surface smooth (6), or asperulous (1), or tuberculate (1), or muricate (5), or rugose (5); without pits; glabrous (11), or pubescent (1). Lower glume apex entire (11), or dentate (3); 2 -fid (3/3); obtuse (1/11), or acute (10/11), or acuminate (2/11); muticous (9), or mucronate (2), or awned (5). Upper glume lanceolate (3), or oblong (9); membranous; 1-keeled (1/1); 3 -veined (10), or 5 -veined (2). Upper glume surface smooth (11), or rugose (1). Upper glume apex acute (1/2), or acuminate (1/2); muticous (7), or mucronate (2), or awned (5); 1 -awned (5/5).

FLORETS Basal sterile florets male (10), or barren (3); with palea. Lemma of lower sterile floret lanceolate (10), or ovate (2); hyaline (11), or membranous (1); 1 -veined (1/5), or 2 -veined (2/5), or 3–4 -veined (1/5); obtuse (1), or acute (11). Fertile lemma lanceolate (8), or elliptic (1), or oblong (3); hyaline (11), or membranous (1); without keel; wingless; 1 -veined (3/7), or 2 -veined (1/7), or 3 -veined (5/7). Lemma surface unwrinkled; without grooves. Lemma margins eciliate (10), or ciliolate (2). Lemma apex acute. Palea present (11), or absent or minute (1); 0.5–0.675–1 length of lemma; hyaline (1/11), or membranous (10/11); 0 -veined (1/1).

FLOWER Lodicules 2 (1/1); fleshy (1/1); truncate (1/1). Anthers 3 (11/11). Stigmas 2 (1/1).

FRUIT Caryopsis with adherent pericarp (1/1); oblong (1/1); isodiametric (1/1). Embryo 0.5 length of caryopsis. Hilum punctiform (1/1).

DISTRIBUTION Africa (9), or North America (2), or South America (4).

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