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.

Orinus

HABIT Perennial. Rhizomes elongated. Culms erect; 15–39.36–75 cm long. Ligule an eciliate membrane. Leaf-blades linear, or lanceolate (1); herbaceous (5), or coriaceous (1).

INFLORESCENCE Inflorescence composed of racemes.

Racemes borne along a central axis; erect (3), or ascending (3), or deflexed (1); unilateral; bearing 7–9 fertile spikelets on each (1/1). Rhachis angular (4/4). Spikelet packing broadside to rhachis.

Spikelets solitary. Fertile spikelets sessile (1), or pedicelled (5). Pedicels oblong (1/1).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets (1), or 2 fertile florets (2), or 3–4 fertile florets (3), or 5–6 fertile florets (2), or 7–8 fertile florets (1); with diminished florets at the apex. Spikelets lanceolate (1), or oblong (2), or ovate (1), or cuneate (2); laterally compressed; 5–7.583–11 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes definite; glabrous (4), or pubescent (2).

GLUMES Glumes persistent; shorter than spikelet; thinner than fertile lemma. Lower glume linear (1), or lanceolate (5); 0.75–0.8333–0.9 length of upper glume; membranous; 1-keeled; 1 -veined, or 3 -veined (1). Lower glume lateral veins absent, or distinct (1). Lower glume surface without pits; glabrous, or pilose (1). Lower glume apex obtuse (1), or acute (3), or acuminate (2). Upper glume lanceolate (3), or ovate (3); 0.8–0.975–1 length of adjacent fertile lemma; membranous (5), or herbaceous (1); with undifferentiated margins (3), or hyaline margins (2), or membranous margins (1); without keels (5), or 1-keeled (1); 3 -veined. Upper glume surface smooth (5), or scabrous (1); glabrous, or pilose (1). Upper glume apex obtuse (1), or acute (3), or acuminate (2).

FLORETS Fertile lemma lanceolate (2), or elliptic (3), or oblong (1); chartaceous; keeled; wingless; 3 -veined. Lemma midvein without distinctive roughness (5), or scaberulous (1); eciliate (4), or pubescent (2). Lemma surface unwrinkled; without grooves; glabrous (1), or pubescent (1), or pilose (2), or villous (2); hairy on back (4/5), or on veins (1/5). Lemma margins eciliate (4), or ciliate (1), or villous (1). Lemma apex entire (5), or dentate (2); 2–3 -fid (1/2); acute; muticous (5), or mucronate (2). Palea 0.8–0.9667–1.1 length of lemma; 2 -veined (5/5). Palea keels smooth (5), or scaberulous (1); eciliate (2), or pubescent (1), or ciliate (3). Palea surface glabrous (4), or pubescent (1), or pilose (1). Palea apex dentate (1/1). Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2 (3/3); fleshy (3/3). Anthers 3.

FRUIT Caryopsis with adherent pericarp; fusiform (1/4), or oblong (3/4); isodiametric (1/1); biconvex (1/1). Embryo 0.33 length of caryopsis. Hilum elliptic (1/1).

DISTRIBUTION Temperate Asia, or Tropical Asia (1).

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