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.

Aristida

HABIT Annual (54), or perennial (235). Rhizomes absent (273), or short (10), or elongated (3). Culms erect (122/141), or geniculately ascending (32/141), or decumbent (7/141), or prostrate (1/141), or rambling (1/141); robust (12/27), or slender (15/27); 2–57.42–200 cm long; firm (262), or wiry (21), or woody (1); without nodal roots (1/2), or rooting from lower nodes (2/2). Culm-internodes similar in length (1/1); terete (11/14), or elliptical in section (3/14). Culm-nodes flush with internodes (1/6), or swollen (5/6). Lateral branches lacking (92/158), or sparse (54/158), or ample (31/158), or fastigiate (9/158), or suffrutescent (1/158). Ligule an eciliate membrane (1), or a ciliolate membrane (11), or a fringe of hairs (273). Leaf-blades aciculate (4), or filiform (58), or linear (231); herbaceous (278), or coriaceous (6); stiff (22), or firm (262). Leaf-blade margins unthickened (2/14), or cartilaginous (12/14). Leaf-blade apex muticous (281), or pungent (3).

INFLORESCENCE Inflorescence a panicle; terminal (283), or terminal and axillary (1); not deciduous as a whole (283), or deciduous as a whole (1); exserted (282), or embraced at base by subtending leaf (5).

Panicle open (160), or contracted (114), or spiciform (26), or capitate (1). Primary panicle branches not whorled (283), or whorled at most nodes (1).

Spikelets appressed (15/16), or spreading (1/16); solitary (247/249), or in pairs (2/249). Fertile spikelets sessile (27/248), or sessile and pedicelled (1/248), or pedicelled (220/248). Pedicels filiform (7/9), or oblong (1/9), or clavate (1/9); tip widened (3/3).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear (112/249), or lanceolate (135/249), or oblong (1/249), or cuneate (1/249); laterally compressed (6), or subterete (278); 2–11.52–66 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus brief (10), or evident (139), or elongated (135); without wings (282), or winged (2); pubescent (182/279), or pilose (67/279), or bearded (30/279); truncate (7), or obtuse (108), or acute (122), or pungent (42), or 2-toothed (11).

GLUMES Glumes persistent (171/182), or lower deciduous, upper persistent (3/182), or deciduous (8/182); shorter than spikelet (34/248), or reaching apex of florets (61/248), or exceeding apex of florets (182/248); thinner than fertile lemma (249), or similar to fertile lemma in texture (35); parallel to lemmas (283), or recurved at apex (1), or gaping (1). Lower glume linear (62), or lanceolate (226), or oblong (2); 0.3–0.8637–4 length of upper glume; membranous (236/249), or chartaceous (3/249), or scarious (10/249); 1-keeled (153/153); 1 -veined (231/269), or 2 -veined (20/269), or 3 -veined (49/269), or 4 -veined (9/269), or 5 -veined (11/269), or 6–7 -veined (5/269). Lower glume lateral veins absent (202), or obscure (9), or distinct (84). Lower glume surface smooth (218), or asperulous (66), or scabrous (60); without pits; glabrous (278), or puberulous (5), or pubescent (4), or pilose (2), or hispidulous (2), or hispid (1), or woolly (1). Lower glume apex entire (262), or dentate (22), or lobed (2); 2 -fid (23/23); emarginate (14/258), or obtuse (19/258), or acute (124/258), or acuminate (122/258), or attenuate (16/258), or setaceously attenuate (48/258), or cuspidate (2/258); muticous (191), or mucronate (51), or awned (73). Upper glume subulate (1), or linear (69), or lanceolate (216), or oblong (3), or cuneate (1); 0.4–1.473–6 length of adjacent fertile lemma; membranous (236/249), or chartaceous (3/249), or scarious (10/249); with undifferentiated margins (283), or hyaline margins (1); without keels (2/151), or 1-keeled (149/151); 1 -veined (262/266), or 2 -veined (8/266), or 3 -veined (12/266). Upper glume primary vein eciliate (283), or ciliolate (1). Upper glume surface smooth (265), or asperulous (31), or scabrous (23); glabrous (281), or puberulous (2), or pubescent (2), or pilose (2), or hispidulous (1), or hispid (1), or woolly (1). Upper glume apex entire (221), or erose (2), or dentate (63), or lobed (3); 2 -fid (65/66), or 3 -fid (1/66); emarginate (26/224), or truncate (7/224), or obtuse (23/224), or acute (100/224), or acuminate (101/224), or attenuate (12/224), or setaceously attenuate (40/224), or caudate (1/224); muticous (166), or mucronate (70), or awned (76); 1 -awned (70/70).

FLORETS Fertile lemma linear (112/250), or lanceolate (79/250), or elliptic (54/250), or oblong (5/250), or ovate (1/250); laterally compressed (14), or subterete (271); oblong in profile (1/1); coriaceous (249/249); without keel (223/256), or keeled (33/256); wingless; 3 -veined (280/281), or 5 -veined (1/281). Lemma midvein without distinctive roughness (263), or scaberulous (9), or scabrous (18). Lemma surface smooth (164), or granulose (4), or asperulous (7), or scaberulous (63), or scabrous (59), or papillose (7), or tuberculate (12), or punctate (4); unwrinkled; without grooves (274), or with a median groove (10); glabrous (280), or puberulous (1), or pubescent (2), or villous (1), or hispid (1). Lemma margins flat (1), or involute (50), or convolute (235); exposing palea (36), or covering most of palea (248). Lemma apex entire (283), or dentate (1); 2 -fid (1/1); acute (137/146), or acuminate (3/146), or attenuate (1/146), or rostrate (5/146); without ornament (282), or scabrous (2); without appendage (272), or with a short cylindrical neck (10), or with outer margin prolonged as a hyaline appendage (2); muticous (1), or awned; 1 -awned (17), or 3 -awned (275). Principal lemma awn apical (283), or from a sinus (1); straight (133), or curved (12), or flexuous (5), or coiled (1), or geniculate (11), or 3-branched (136); attenuate (283), or pungent (1). Column of lemma awn glabrous (126/128), or puberulous (1/128), or pubescent (2/128). Lateral lemma awns subequal to principal (139/275), or shorter than principal (148/275). Palea present (283), or absent or minute (1); 0.1–0.1836–1 length of lemma; hyaline (11/283), or membranous (272/283); 0 -veined (8/14), or 2 -veined (6/14); without keels (131/283), or 2-keeled (152/283). Palea apex entire (1/2), or dentate (2/2).

FLOWER Lodicules 2 (20/20); membranous (1/2), or fleshy (1/2); glabrous (19/20), or ciliate (1/20); truncate (1/3), or obtuse (1/3), or acute (1/3). Anthers 3 (232/232).

FRUIT Caryopsis with adherent pericarp (101/101); linear (10/32), or lanceolate (1/32), or fusiform (20/32), or ellipsoid (1/32). Embryo 0.2–0.335–0.5 length of caryopsis. Hilum linear (72/73), or curved (1/73); 0.2–0.4653–1 length of caryopsis.

DISTRIBUTION Europe (1), or Africa (70), or Temperate Asia (23), or Tropical Asia (25), or Australasia (59), or Pacific (5), or North America (50), or South America (100).

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