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.

Trachys

HABIT Annual, or perennial (1). Culms geniculately ascending (1), or decumbent; 15–26.25–40 cm long; rooting from lower nodes (1/1). Ligule an eciliate membrane (1), or a fringe of hairs (1). Leaf-blades linear, or lanceolate (1).

INFLORESCENCE Inflorescence composed of racemes.

Racemes single (1), or paired, or digitate (1); unilateral. Rhachis fragile at the nodes; broadly winged; foliaceous.

Spikelets in threes (1), or subtended by an involucre (1). Fertile spikelets sessile; 2 in the cluster (1), or 3 in the cluster, or 4–6 in the cluster (1). Companion sterile spikelets sessile (1/1); 2–6 in the cluster (1/1). Involucre composed of imperfect spikelets (1/1). Pedicels oblong (1/1).

STERILE SPIKELETS Companion sterile spikelets absent (1), or well-developed (1); deciduous with the fertile (1/1).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 3–4.3–6 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes shorter than spikelet; thinner than fertile lemma. Lower glume subulate (1), or ovate (1); coriaceous (1/1); 0 -veined (1/1). Lower glume lateral veins absent (1), or distinct (1). Lower glume surface without pits. Upper glume lanceolate; 0.5–0.65–0.8 length of adjacent fertile lemma; membranous (1), or chartaceous (1); 3 -veined. Upper glume apex acute, or acuminate (1).

FLORETS Basal sterile florets barren; with palea (1), or without significant palea (1). Lemma of lower sterile floret lanceolate (1), or ovate; coriaceous; 9–10 -veined (1), or 11–13 -veined; acute (1), or cuspidate (1). Palea of lower sterile floret membranous (1/1). Fertile lemma ovate; chartaceous (1), or cartilaginous (1); of similar consistency on margins (1), or much thinner on margins (1); without keel; wingless; 3 -veined (1), or 5 -veined (1). Lemma surface unwrinkled; without grooves. Lemma apex acute. Palea cartilaginous.

FLOWER Lodicules 2 (1/1); membranous (1/1). Anthers 3 (1/1).

FRUIT Caryopsis with adherent pericarp (1/1); oblong (1/1). Embryo 0.5 length of caryopsis. Hilum punctiform (1/1).

DISTRIBUTION Tropical Asia.

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