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.

Holcus

HABIT Annual (2), or perennial (6). Rhizomes absent (6), or short (1), or elongated (1). Culms erect (5/6), or geniculately ascending (6/6), or decumbent (1/6); 8–50.5–120 cm long. Ligule an eciliate membrane. Leaf-blades stiff (1), or firm (7).

INFLORESCENCE Inflorescence a panicle.

Panicle open (4), or contracted (4).

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets (7), or 2 fertile florets (1); with a barren rhachilla extension (1), or with diminished florets at the apex (7). Spikelets elliptic, or oblong (1); laterally compressed; 3–5.406–11 mm long; falling entire. Rhachilla internodes brief up to lowest fertile floret (1), or elongated below proximal fertile floret (7); definite (1/1). Floret callus pubescent (1/6), or pilose (4/6), or bearded (1/6).

GLUMES Glumes exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate (5), or elliptic (3); 0.75–0.9844–1 length of upper glume; chartaceous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface smooth (5), or asperulous (3); without pits; glabrous (5), or puberulous (1), or pubescent (2). Lower glume apex obtuse (2), or acute (4), or acuminate (3), or setaceously attenuate (1); muticous (5), or awned (3). Upper glume lanceolate (1), or elliptic (6), or oblong (1), or ovate (1); 2–2.125–3.5 length of adjacent fertile lemma; chartaceous; 1-keeled; 3 -veined. Upper glume primary vein eciliate (3), or ciliolate (1), or ciliate (4). Upper glume lateral veins without ribs (7), or ribbed (1). Upper glume surface smooth (4), or asperulous (3), or scabrous (1); glabrous (2), or puberulous (1), or pubescent (5). Upper glume apex entire, or dentate (1); 2 -fid (1/1); obtuse (2), or acute (2), or acuminate (3), or setaceously attenuate (1); muticous (2), or mucronate (3), or awned (3); 1 -awned (3/3).

FLORETS Fertile lemma elliptic (5), or ovate (3); cartilaginous; without keel (1/7), or keeled (6/7); wingless; 3–4 -veined (6), or 5 -veined. Lemma lateral veins obscure (7/7). Lemma surface unwrinkled; without grooves; glabrous, or puberulous (1). Lemma apex obtuse (7), or acute (1); muticous (6), or awned (2); 1 -awned (2/2). Principal lemma awn subapical (1/2), or dorsal (1/2); geniculate (2/2). Palea 1 length of lemma. Apical sterile florets 1 in number (7/7); male (6/7), or barren (1/7); linear (1/7), or elliptic (5/7), or ovate (1/7). Apical sterile lemmas awned (7/7). Apical sterile lemma awns straight (2/7), or geniculate (3/7), or hooked (2/7).

FLOWER Anthers 3. Ovary glabrous.

DISTRIBUTION Europe (6), or Africa (5), or Temperate Asia (2), or Tropical Asia (2), or Australasia (4), or Pacific (1), or North America (2), or South America (1), or Antarctica (1).

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