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.

Trisetum

HABIT Perennial. Rhizomes absent (72), or short (9), or elongated (9). Stolons absent (82), or present (6). Culms erect (36/44), or geniculately ascending (19/44), or rambling (1/44); robust (3/12), or slender (8/12), or weak (1/12); 2–48.92–300 cm long; without nodal roots (2/2), or rooting from lower nodes (2/2). Culm-nodes constricted (3/3). Lateral branches lacking (8/9), or sparse (3/9), or ample (1/9). Ligule an eciliate membrane (74), or a ciliolate membrane (15). Leaf-blades filiform (5), or linear (83); herbaceous (86), or coriaceous (2); stiff (13), or firm (73), or flaccid (2). Leaf-blade midrib conspicuous (2/2). Leaf-blade margins unthickened (2/3), or cartilaginous (1/3). Leaf-blade apex muticous (87), or pungent (1).

INFLORESCENCE Inflorescence a panicle; exserted, or embraced at base by subtending leaf (1).

Panicle open (44/87), or contracted (28/87), or spiciform (21/87). Primary panicle branches not whorled (80), or whorled at most nodes (8).

Spikelets appressed (2/2); solitary. Fertile spikelets pedicelled. Pedicels filiform (1/2), or oblong (1/2).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets (7), or 2 fertile florets (77), or 3 fertile florets (64), or 4 fertile florets (11), or 5 fertile florets (5), or 6 fertile florets (2); with a barren rhachilla extension (81), or with diminished florets at the apex (9). Spikelets lanceolate (1), or oblong (84), or cuneate (8); laterally compressed; 3–6.357–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes definite (87/87); glabrous (12/87), or sparsely hairy (4/87), or pubescent (25/87), or pilose (47/87), or villous (2/87). Floret callus glabrous (2/74), or pubescent (62/74), or pilose (7/74), or bearded (3/74); truncate (1), or obtuse (87).

GLUMES Glumes persistent; shorter than spikelet (57), or reaching apex of florets (31), or exceeding apex of florets (9); thinner than fertile lemma (84), or similar to fertile lemma in texture (4), or firmer than fertile lemma (1); parallel to lemmas (9), or gaping (79). Lower glume linear (6), or lanceolate (64), or elliptic (14), or oblong (5), or ovate (4); 0.25–1.628–75 length of upper glume; hyaline (5), or membranous (83); 1-keeled (87/87); 1 -veined (67/79), or 2 -veined (7/79), or 3 -veined (19/79). Lower glume lateral veins absent (66), or obscure (6), or distinct (22). Lower glume surface smooth (86), or asperulous (1), or scabrous (1); without pits. Lower glume apex obtuse (1/87), or acute (63/87), or acuminate (22/87), or attenuate (1/87), or setaceously attenuate (6/87); muticous (86), or mucronate (2), or awned (1). Upper glume linear (1), or lanceolate (47), or elliptic (33), or oblong (7), or ovate (8), or obovate (1); 0.66–1.042–2.5 length of adjacent fertile lemma; hyaline (5), or membranous (83); with undifferentiated margins (77), or hyaline margins (11); 1-keeled (87/87); 1 -veined (2/80), or 2 -veined (1/80), or 3 -veined (78/80), or 4 -veined (2/80), or 5 -veined (3/80). Upper glume primary vein eciliate (85), or ciliolate (1), or ciliate (2). Upper glume surface smooth (85), or asperulous (1), or scabrous (2). Upper glume apex entire (87), or erose (1); obtuse (3/87), or acute (70/87), or acuminate (14/87), or setaceously attenuate (6/87); muticous (85), or mucronate (3), or awned (1); 1 -awned (1/1).

FLORETS Fertile lemma lanceolate (20), or elliptic (32), or oblong (33), or ovate (3), or obovate (3); membranous (81), or chartaceous (4), or cartilaginous (3); of similar consistency above (74), or much thinner above (14); of similar consistency on margins (71), or much thinner on margins (17); without keel (5), or keeled (83); wingless; 3 -veined (2), or 5 -veined (86), or 6–7 -veined (1). Lemma midvein without distinctive roughness (82), or scaberulous (5), or scabrous (1); eciliate (87), or ciliate (1). Lemma lateral veins obscure (4/6), or prominent (2/6); excurrent (7/7), or extending close to apex (1/7). Lemma surface smooth (51), or asperulous (12), or scaberulous (11), or scabrous (9), or papillose (6); unwrinkled (87), or rugose (1); without grooves; glabrous (76), or puberulous (2), or pubescent (7), or pilose (5), or hirsute (2). Lemma apex entire (7), or dentate (81), or lobed (1); 2 -fid (80/82), or 3 -fid (1/82), or 4 -fid (3/82); incised 0.15–0.24–0.33 of lemma length; obtuse (2/6), or acute (3/6), or acuminate (1/6), or setaceously attenuate (1/6); muticous (3), or mucronate (2), or awned (86); 1 -awned (71/86), or 3 -awned (14/86), or 5 -awned (1/86). Principal lemma awn subapical (3), or dorsal (85); straight (14), or curved (31), or flexuous (3), or geniculate (53); limb glabrous (86), or puberulous (1), or ciliate (1). Column of lemma awn glabrous (50/52), or puberulous (1/52), or pubescent (1/52). Lateral lemma awns shorter than principal (1/1). Palea embraced by lemma (8), or gaping (80); 0.5–0.8636–1 length of lemma; hyaline (82), or membranous (6). Palea keels smooth (49), or scaberulous (37), or scabrous (3); eciliate (78), or ciliolate (6), or ciliate (4). Palea surface glabrous (86), or pubescent (1), or pilose (1). Palea apex erose (1/3), or dentate (2/3); muticous (81), or with excurrent keel veins (7). Apical sterile florets resembling fertile though underdeveloped (6/9), or distinct from fertile (3/9).

FLOWER Lodicules 2 (27/27); membranous (5/5); glabrous (25/27), or ciliate (3/27); entire (1/5), or 2-toothed (5/5); emarginate (1/2), or truncate (1/2). Anthers 3. Ovary glabrous (42/50), or with a few apical hairs (1/50), or pubescent on apex (7/50), or pubescent all over (1/50).

FRUIT Caryopsis with adherent pericarp (79/79); linear (1/6), or fusiform (3/6), or oblong (2/6); apex rostrate (1/1). Embryo 0.2 length of caryopsis. Hilum punctiform (55/57), or elliptic (1/57), or linear (1/57).

DISTRIBUTION Europe (19), or Africa (3), or Temperate Asia (24), or Tropical Asia (8), or Australasia (10), or Pacific (3), or North America (21), or South America (26), or Antarctica (1).

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