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.

Oropetium

HABIT Annual (3), or perennial (3). Culms erect; 1–8.416–25 cm long. Ligule an eciliate membrane (1), or a ciliolate membrane (4), or a ciliate membrane (1). Leaf-blades filiform (3), or linear (3); stiff (3), or firm (3).

INFLORESCENCE Inflorescence composed of racemes; not deciduous as a whole (5), or deciduous as a whole (1); exserted (4), or embraced at base by subtending leaf (2).

Racemes single; unilateral (1/3), or bilateral (3/3). Rhachis tough (2), or fracturing into irregular segments (3), or fragile at the nodes (1); semiterete (1), or subcylindrical and excavated (5). Spikelet packing adaxial; 2 -rowed. Rhachis internodes indefinite (5), or linear (1).

Spikelets sunken; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension (5), or with a barren rhachilla extension (1), or with diminished florets at the apex (1). Spikelets lanceolate (5), or elliptic (1); dorsally compressed; 1.66–2.956–4.8 mm long; falling entire (1), or breaking up at maturity (5); deciduous with accessory branch structures (1/1); disarticulating below each fertile floret (5/5). Floret callus pubescent.

GLUMES Glumes one the lower absent or obscure (1), or two; deciduous (5/5); reaching apex of florets (1), or exceeding apex of florets (5); firmer than fertile lemma; parallel to lemmas (5), or recurved at apex (4). Lower glume linear (1), or oblong (4), or orbicular (1); 0–0.2167–0.5 length of upper glume; hyaline; without keels; 0 -veined (5), or 1 -veined (1). Lower glume lateral veins absent. Lower glume surface without pits. Lower glume apex truncate (4/5), or obtuse (1/5), or acute (1/5). Upper glume lanceolate (5), or elliptic (1); 1–1.508–3 length of adjacent fertile lemma; herbaceous (3), or coriaceous (3); with undifferentiated margins (5), or hyaline margins (1); without keels; 1–2 -veined (1), or 3 -veined. Upper glume lateral veins without ribs (4), or ribbed (2). Upper glume apex obtuse (1), or acute (3), or acuminate (2); muticous (4), or awned (2); 1 -awned (2/2).

FLORETS Fertile lemma elliptic (2), or oblong (4), or obovate (1); hyaline (2), or membranous (4); without keel; wingless; 1–2 -veined (1), or 3 -veined. Lemma surface unwrinkled; without grooves; glabrous (4), or pubescent (1), or pilose (1). Lemma apex entire (1), or dentate (5); 2 -fid (5/5), or 3 -fid (1/5); truncate (1/1); muticous (2), or mucronate (3), or awned (1); 1 -awned (1/1). Principal lemma awn apical (3/4), or from a sinus (1/4). Palea 1 length of lemma; hyaline; 2 -veined. Palea surface glabrous (5), or pilose (1). Palea apex muticous (5), or with excurrent keel veins (1). Apical sterile florets 1 in number (1/1); male (1/1); oblong (1/1).

FLOWER Anthers 3 (2/2).

FRUIT Caryopsis with tardily free pericarp; fusiform (3/5), or ellipsoid (1/5), or oblong (1/5), or obovoid (1/5).

DISTRIBUTION Africa (4), or Temperate Asia (3), or Tropical Asia (3).

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