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.

Rottboellia

HABIT Annual (5), or perennial (1). Culms erect (3/4), or geniculately ascending (1/4); robust (1/1); 30–153.3–300 cm long; with prop roots (3/4), or rooting from lower nodes (1/4). Culm-internodes terete (1/1), or channelled (1/1). Lateral branches ample (2/2). Ligule an eciliate membrane (3), or a ciliolate membrane (3). Leaf-blades linear (5), or lanceolate (3); stiff (1), or firm (4), or flaccid (1).

INFLORESCENCE Inflorescence composed of racemes; terminal (1), or terminal and axillary (5); subtended by an unspecialized leaf-sheath (2), or an inflated leaf-sheath (4); exserted, or embraced at base by subtending leaf (1). Peduncle widened at apex (4/4).

Racemes single; erect (1), or ascending (5); unilateral (5/5). Rhachis fragile at the nodes; subcylindrical and excavated (5/5); terminating in a spikelet (2), or sterile spikelet (4). Spikelet packing abaxial (5/5). Rhachis internodes oblong (5), or cuneate (1). Rhachis internode tip transverse; crateriform.

Spikelets sunken (5), or appressed (1); in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels free (1), or fused to internode; columnar (2), or oblong (4).

STERILE SPIKELETS Companion sterile spikelets rudimentary (2), or well-developed (5); deciduous with the fertile (5/5). Companion sterile spikelet glumes muticous (5/5).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong (4), or ovate (2); dorsally compressed; symmetrical (2), or gibbous (4); 3–5.791–10 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous (5/5); base truncate; with central boss (1), or with central peg (5); attached transversely.

GLUMES Glumes reaching apex of florets (5), or exceeding apex of florets (1); firmer than fertile lemma. Lower glume oblong (4), or ovate (2); coriaceous (2), or indurate (4); 2-keeled; wingless (3), or winged on keel (3); 7–8 -veined (1/4), or 9 -veined (2/4), or 10–12 -veined (1/4), or 13 -veined (2/4), or 14–16 -veined (1/4). Lower glume lateral veins distinct (5), or prominent (1). Lower glume surface convex (4), or flat (2), or concave (1); smooth (5), or asperulous (1); without pits. Lower glume apex emarginate (2/5), or obtuse (2/5), or acute (1/5). Upper glume ovate; not gibbous (4), or gibbous (2); 1 length of adjacent fertile lemma; chartaceous; without keels (1), or 1-keeled (5); wingless (4), or winged on keel (2); 9–10 -veined (2/3), or 11 -veined (3/3). Upper glume apex acute.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret oblong (1), or ovate (5); 1 length of fertile lemma; hyaline (5), or membranous (1); 1 -veined (1/5), or 3 -veined (3/5), or 4 -veined (1/5), or 5 -veined (2/5); obtuse (1/5), or acute (4/5). Palea of lower sterile floret hyaline (5), or membranous (1). Fertile lemma oblong (1/5), or ovate (3/5), or oblate (1/5); laterally compressed (1/1); not gibbous (4), or gibbous (2); hyaline (5), or membranous (1); without keel (1/2), or keeled (1/2); wingless; 1 -veined (4), or 3 -veined (2). Lemma surface unwrinkled; without grooves. Lemma apex obtuse (1/5), or acute (4/5). Palea 0.5–0.8333–1 length of lemma; hyaline (5), or membranous (1); 0 -veined (1/1); without keels (5), or 2-keeled (1).

FLOWER Lodicules 2 (1/1); fleshy (1/1). Anthers 3. Stigmas 2 (2/2).

FRUIT Caryopsis with tardily free pericarp (1/1); ovoid (1/1). Embryo 0.5 length of caryopsis. Hilum punctiform (1/1).

DISTRIBUTION Africa (2), or Temperate Asia (2), or Tropical Asia (3), or Australasia (2), or Pacific (1), or North America (1), or South America (1).

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