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.

Microstegium

HABIT Annual (16), or perennial (10). Rhizomes absent (25), or elongated (1). Culms erect (2/24), or geniculately ascending (2/24), or decumbent (5/24), or prostrate (4/24), or rambling (12/24), or scandent (1/24); robust (3/8), or slender (4/8), or weak (1/8); 10–70.27–400 cm long; rooting from lower nodes (18/18). Culm-internodes terete (1/1). Lateral branches lacking (1/9), or sparse (1/9), or ample (7/9). Ligule an eciliate membrane (22), or a ciliolate membrane (3), or a fringe of hairs (1). Leaf-blade base without a false petiole (21), or with a brief petiole-like connection to sheath (2), or with a false petiole (3). Leaf-blades linear (7), or lanceolate (21), or elliptic (7), or oblong (2), or ovate (3); stiff (1), or firm (19), or flaccid (6).

INFLORESCENCE Inflorescence composed of racemes.

Racemes single (5), or paired (3), or digitate (22); erect (1), or ascending (22), or spreading (4), or drooping (2). Rhachis tough (4), or fragile at the nodes (22); wingless (25), or narrowly winged (1); flattened (5/10), or angular (3/10), or semiterete (2/10). Spikelet packing contiguous (25), or lax (1). Rhachis internodes filiform (8), or linear (13), or columnar (1), or clavate (1), or cuneate (2), or pyriform (2). Rhachis internode tip cupuliform (1/1).

Spikelets appressed (9/9); in pairs. Fertile spikelets sessile (2), or sessile and pedicelled (22), or pedicelled (2); 1 in the cluster (1), or 2 in the cluster (25); subequal (1/3), or the upper smaller (2/3). Companion sterile spikelets pedicelled (2/2); 1 in the cluster (2/2). Pedicels filiform (8), or linear (13), or clavate (4), or cuneate (1); tip widened (1/1).

STERILE SPIKELETS Basal sterile spikelets absent (25), or well-developed (1).

Companion sterile spikelets absent (24), or rudimentary (1), or well-developed (2).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (17), or elliptic (4), or oblong (7); laterally compressed (1), or dorsally compressed (25); 1.66–4.354–7 mm long; falling entire; deciduous from the base (25), or with accessory branch structures (22). Spikelet callus brief (24), or square (2); glabrous (3/19), or pubescent (6/19), or pilose (7/19), or bearded (5/19); base obtuse; attached transversely (25/25).

GLUMES Glumes exceeding apex of florets (2/2); firmer than fertile lemma. Lower glume linear (2), or lanceolate (3), or elliptic (14), or oblong (9); chartaceous (2), or cartilaginous (2), or coriaceous (22); 2-keeled; wingless (25), or winged on keel (1); 2–3 -veined (2/17), or 4 -veined (11/17), or 5 -veined (4/17), or 6–7 -veined (5/17), or 8 -veined (3/17), or 9 -veined (1/17). Lower glume lateral veins obscure (1), or distinct (25); without ribs (25), or ribbed (1); intercarinal veins distinct (2/3), or absent below, prominent above (1/3). Lower glume surface flat (3), or concave (8), or with a longitudinal median groove (16); smooth (19), or asperulous (3), or scabrous (5); without pits; glabrous (22), or puberulous (1), or pilose (3). Lower glume apex entire (21), or dentate (7); 2 -fid (7/7); emarginate (7/19), or truncate (1/19), or obtuse (7/19), or acute (5/19), or acuminate (1/19). Upper glume lanceolate (1), or elliptic (23), or oblong (2); membranous (3/7), or chartaceous (5/7), or cartilaginous (2/7); with undifferentiated margins (25), or hyaline margins (1); without keels (3/25), or 1-keeled (24/25); 1–2 -veined (1/16), or 3 -veined (14/16), or 4 -veined (1/16), or 5 -veined (2/16), or 6 -veined (1/16), or 7 -veined (2/16). Upper glume primary vein eciliate (22), or ciliolate (1), or ciliate (3). Upper glume lateral veins with cross-veins (1/1). Upper glume surface smooth (25), or scabrous (1); glabrous (24), or pilose (2). Upper glume apex entire (23), or dentate (3); 2 -fid (3/3); acute (12/17), or acuminate (4/17), or attenuate (2/17); muticous (15), or mucronate (3), or awned (9); 1 -awned (9/9).

FLORETS Basal sterile florets male (9/21), or barren (15/21); with palea (10/20), or without significant palea (10/20). Lemma of lower sterile floret linear (3/17), or lanceolate (10/17), or oblong (5/17); hyaline (18/18); 0 -veined (2/3), or 1 -veined (1/3), or 3 -veined (1/3); obtuse (2/3), or acuminate (1/3); muticous (16/17), or awned (1/17). Palea of lower sterile floret hyaline (8/10), or membranous (2/10). Fertile lemma linear (9), or lanceolate (4), or oblong (8), or ovate (1), or orbicular (5); hyaline (25), or membranous (1); without keel; wingless; 0 -veined (11/13), or 3 -veined (2/13). Lemma surface unwrinkled; without grooves; glabrous (25), or pubescent (1). Lemma margins eciliate (23), or ciliolate (1), or ciliate (2). Lemma apex entire (6), or dentate (13), or lobed (8); 2 -fid (21/21); incised 0.25–0.4575–0.75 of lemma length; emarginate (2/5), or acuminate (3/5); muticous (2), or mucronate (1), or awned (24); 1 -awned (24/24). Principal lemma awn apical (6/25), or from a sinus (20/25); straight (2/25), or flexuous (7/25), or geniculate (16/25); attenuate (23/25), or with thread-like crinkled tip (2/25). Palea present (15), or absent or minute (11); 0.33–0.8883–1 length of lemma; hyaline (9/15), or membranous (6/15); 0 -veined (1/1); without keels (2/15), or 2-keeled (13/15). Palea surface glabrous (13/15), or pilose (2/15). Palea apex dentate (2/2).

FLOWER Lodicules 2 (5/5). Anthers 2 (6/22), or 3 (16/22).

FRUIT Caryopsis with adherent pericarp (3/3); fusiform (1/2), or obovoid (1/2). Embryo 0.25–0.375–0.5 length of caryopsis. Hilum punctiform (1/1).

DISTRIBUTION Africa (3), or Temperate Asia (15), or Tropical Asia (19), or Australasia (1), or Pacific (3), or North America (1).

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