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.

Paractaenum

HABIT Annual. Culms erect, or decumbent; 30–60 cm long. Ligule a ciliolate membrane. Leaf-blades flaccid.

INFLORESCENCE Inflorescence composed of racemes.

Racemes borne along a central axis; spreading, or deflexed; unilateral; bearing few fertile spikelets; bearing 1–4 fertile spikelets on each. Central inflorescence axis flattened. Rhachis deciduous from axis; narrowly winged; angular; terminating in a barren extension; extension subulate. Spikelet packing abaxial; distant. Raceme-bases cuneate.

Spikelets appressed; subtended by an involucre. Fertile spikelets pedicelled; 1 in the cluster. Involucre composed of bristles. Involucral bristles deciduous with the fertile spikelets. Pedicels oblong.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 3.5–5 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes reaching apex of florets; thinner than fertile lemma. Lower glume ovate; membranous; without keels; 3–7 -veined. Lower glume surface without pits. Lower glume apex truncate, or obtuse. Upper glume ovate; membranous; without keels; 11 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; with palea, or without significant palea. Lemma of lower sterile floret ovate; membranous; 9–11 -veined; acute. Fertile lemma elliptic; coriaceous; without keel; wingless. Lemma surface striate, or punctate; unwrinkled; without grooves. Lemma margins involute. Palea coriaceous.

FLOWER Lodicules 2; fleshy; truncate. Anthers 3.

DISTRIBUTION Australasia.

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