Trachys

HABIT Annual, or perennial (1). Stolons absent (2), or present (1). Culms geniculately ascending (1), or decumbent; 15–36.5–79 cm long; rooting from lower nodes (2/2). Ligule an eciliate membrane (1), or a fringe of hairs (2). Leaf-blades linear, or lanceolate (2).

INFLORESCENCE Inflorescence composed of racemes.

Racemes single (1), or paired, or digitate (1); unilateral. Rhachis fragile at the nodes; broadly winged; herbaceous (1), or foliaceous (2). Rhachis internodes indefinite (2), or oblong (1).

Spikelets in threes (1), or subtended by an involucre (2). Fertile spikelets sessile; 2 in the cluster (2), or 3 in the cluster, or 4–6 in the cluster (2), or 7 in the cluster (1). Companion sterile spikelets sessile (2/2); 2–6 in the cluster (2/2), or 7 in the cluster (1/2). Involucre composed of imperfect spikelets (2/2). Pedicels columnar (1/2), or oblong (1/2).

STERILE SPIKELETS Companion sterile spikelets absent (1), or well-developed (2); deciduous with the fertile (2/2).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (1), or ovate (2); dorsally compressed; 3–4.366–6 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes shorter than spikelet; thinner than fertile lemma. Lower glume subulate (1), or ovate (2); coriaceous (2/2); 0 -veined (2/2). Lower glume lateral veins absent (2), or distinct (1). Lower glume surface without pits. Lower glume apex obtuse (1/1). Upper glume lanceolate; 0.5–0.65–0.8 length of adjacent fertile lemma; membranous (1), or chartaceous (2); 3 -veined. Upper glume apex acute (2), or acuminate (2).

FLORETS Basal sterile florets barren; with palea (2), or without significant palea (1). Lemma of lower sterile floret lanceolate (2), or ovate (2); coriaceous; 9–10 -veined (2), or 11 -veined, or 12–13 -veined (2); acute (1), or acuminate (1), or cuspidate (1). Palea of lower sterile floret membranous (2/2). Fertile lemma lanceolate (1), or ovate (2); membranous (1), or chartaceous (1), or cartilaginous (1); of similar consistency on margins (2), or much thinner on margins (1); without keel; wingless; 3 -veined (2), or 5 -veined (1). Lemma surface unwrinkled; without grooves. Lemma margins flat (2), or involute (1). Lemma apex acute (2), or acuminate (1). Palea chartaceous (1), or cartilaginous (2).

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

FRUIT Caryopsis with adherent pericarp (1/1); lanceolate (1/2), or oblong (2/2). Embryo 0.5 length of caryopsis. Hilum punctiform (1/1).

DISTRIBUTION Tropical Asia.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.