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.

Helictotrichon

HABIT Perennial. Rhizomes absent (77), or short (18), or elongated (13). Stolons absent (99), or present (3). Culms erect (45/48), or geniculately ascending (13/48), or decumbent (4/48); robust (3/13), or slender (10/13); 10–61.48–160 cm long; without nodal roots (1/1), or rooting from lower nodes (1/1). Culm-internodes terete (14/19), or elliptical in section (12/19). Culm-nodes constricted (1/1). Lateral branches lacking (25/25). Leaf-sheaths open for most of their length (4/10), or tubular for much of their length (6/10). Ligule an eciliate membrane (85), or a ciliolate membrane (18), or a ciliate membrane (1), or a fringe of hairs (2). Leaf-blades persistent (101), or deciduous at the ligule (1); aciculate (2), or filiform (18), or linear (85); herbaceous (101), or fleshy (1); stiff (14), or firm (85), or flaccid (4); without exudate (100), or pruinose (3). Leaf-blade midrib indistinct (1/2), or conspicuous (1/2). Leaf-blade margins unthickened (1/8), or cartilaginous (7/8). Leaf-blade apex muticous (97), or pungent (5).

INFLORESCENCE Inflorescence a panicle; exserted (98), or embraced at base by subtending leaf (4).

Panicle open (77), or contracted (28).

Spikelets solitary. Fertile spikelets sessile (2), or pedicelled (101). Pedicels filiform (1/9), or linear (3/9), or clavate (5/9); tip widened (1/1).

FERTILE SPIKELETS Spikelets comprising 2–4–10 fertile florets; with a barren rhachilla extension (36), or with diminished florets at the apex (75). Spikelets lanceolate (2), or elliptic (1), or oblong (91), or cuneate (10); laterally compressed; 5–13.94–34 mm long; breaking up at maturity; disarticulating below each fertile floret (97), or above glumes but not between florets (5). Rhachilla internodes definite; glabrous (20), or pubescent (7), or pilose (73), or villous (4). Floret callus brief (99), or evident (2), or elongated (1); pubescent (16/86), or pilose (69/86), or bearded (1/86).

GLUMES Glumes persistent; shorter than spikelet (94), or reaching apex of florets (9), or exceeding apex of florets (1); thinner than fertile lemma. Lower glume linear (2), or lanceolate (55), or elliptic (45), or oblong (2), or ovate (1); 0.5–0.7751–1.1 length of upper glume; hyaline (5), or membranous (91), or chartaceous (2), or herbaceous (4); without keels (2), or 1-keeled (100); 1 -veined (58), or 2 -veined (13), or 3 -veined (56), or 4 -veined (7), or 5 -veined (6). Lower glume lateral veins absent (57), or obscure (5), or distinct (52). Lower glume surface smooth (99), or asperulous (2), or scabrous (1); without pits. Lower glume apex obtuse (1), or acute (76), or acuminate (27), or setaceously attenuate (2); muticous (100), or mucronate (3). Upper glume lanceolate (46), or elliptic (50), or oblong (8), or ovate (1); 0.5–1.004–1.5 length of adjacent fertile lemma; hyaline (5), or membranous (91), or chartaceous (2), or herbaceous (4); with undifferentiated margins (87), or hyaline margins (14), or membranous margins (1); without keels (2), or 1-keeled (100); 1 -veined (1), or 3 -veined (89), or 4 -veined (14), or 5 -veined (25), or 6 -veined (5), or 7 -veined (6). Upper glume surface smooth (96), or asperulous (6), or scabrous (1), or papillose (1). Upper glume apex acute (78), or acuminate (22), or setaceously attenuate (2); muticous (99), or mucronate (4), or awned (1); 1 -awned (1/1).

FLORETS Fertile lemma lanceolate (18), or elliptic (54), or oblong (26), or ovate (2), or obovate (4); membranous (2), or chartaceous (5), or herbaceous (4), or cartilaginous (92), or coriaceous (2); of similar consistency above (90), or much thinner above (12); of similar consistency on margins (97), or much thinner on margins (5); without keel (101), or keeled (1); wingless; 5 -veined (75/100), or 6 -veined (45/100), or 7 -veined (69/100), or 8 -veined (5/100), or 9 -veined (6/100), or 10–11 -veined (1/100). Lemma midvein without distinctive roughness (101), or scabrous (1); eciliate (99), or ciliolate (1), or ciliate (2). Lemma lateral veins obscure (2/6), or distinct (1/6), or prominent (3/6); without ribs (100), or ribbed (2); excurrent (3/3). Lemma surface smooth (64), or granulose (6), or asperulous (3), or scaberulous (14), or scabrous (15), or papillose (4), or tuberculate (1); unwrinkled; without grooves; glabrous (94), or puberulous (5), or pubescent (5), or pilose (1), or hispidulous (1), or hispid (1). Lemma apex entire (4), or erose (1), or dentate (96), or lobed (2); 2 -fid (90/98), or 3 -fid (3/98), or 4 -fid (11/98); incised 0.25 of lemma length; emarginate (1/28), or obtuse (5/28), or acute (13/28), or acuminate (1/28), or attenuate (1/28), or setaceously attenuate (13/28); awned; 1 -awned (82), or 3 -awned (18), or 5 -awned (2). Principal lemma awn subapical (1), or dorsal; straight (4), or curved (2), or flexuous (2), or geniculate (95). Column of lemma awn glabrous (91/96), or puberulous (2/96), or pubescent (1/96), or hirtellous (2/96). Lateral lemma awns shorter than principal (4/4). Palea embraced by lemma (101), or gaping (1); 0.3–0.8187–1 length of lemma; hyaline (1), or membranous (101); 2 -veined (1/1). Palea keels wingless (101), or winged (1); smooth (99), or scabrous (3); eciliate (26), or pubescent (6), or ciliolate (63), or ciliate (8). Palea surface glabrous (101), or puberulous (1). Palea apex dentate (2/2). Apical sterile florets resembling fertile though underdeveloped (66/75), or distinct from fertile (9/75); rudimentary (8/8).

FLOWER Lodicules 2 (22/22); membranous (9/9); glabrous (22/22), or ciliate (1/22); entire (1/1); obtuse (1/9), or acute (9/9). Anthers 1–2 (1), or 3. Stigmas 2 (1/1). Ovary glabrous (9/99), or pubescent on apex (87/99), or pubescent all over (3/99).

FRUIT Caryopsis with adherent pericarp (95/95); fusiform (1/5), or ellipsoid (1/5), or oblong (3/5). Embryo 0.1–0.241–0.35 length of caryopsis. Hilum punctiform (1/92), or linear (91/92); 0.2–0.3472–0.5 length of caryopsis.

CLEISTOGENES AND VIVIPARY Cleistogenes absent, or present (1); in upper sheaths (1/1), or in lower sheaths (1/1).

DISTRIBUTION Europe (38), or Africa (31), or Temperate Asia (30), or Tropical Asia (7), or Australasia (10), or North America (4), or South America (2).

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