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.

Pentarrhaphis

HABIT Annual (1), or perennial (2). Culms erect; 10–20.83–30 cm long. Ligule a fringe of hairs. Leaf-blades herbaceous (2), or coriaceous (1); stiff (1), or firm (2).

INFLORESCENCE Inflorescence composed of racemes; terminal (2), or terminal and axillary (1).

Racemes borne along a central axis; cuneate; bearing few fertile spikelets; bearing 1 fertile spikelets on each (2), or 2 fertile spikelets on each (1). Central inflorescence axis unspecialized (2), or flattened (1); tip filiform. Rhachis deciduous from axis; terminating in a barren extension; extension a forked bristle.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster (2), or 2 in the cluster (1). Companion sterile spikelets sessile (2/2); 1 in the cluster (2/2).

STERILE SPIKELETS Companion sterile spikelets absent (1), or represented by awns (2).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets cuneate; dorsally compressed; 3–4.27–6 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded.

GLUMES Lower glume subulate. Lower glume surface without pits; hispid. Upper glume subulate. Upper glume surface smooth (2), or scabrous (1); glabrous (1), or hispid (2).

FLORETS Fertile lemma elliptic; cartilaginous; without keel; wingless; 3 -veined. Lemma surface unwrinkled; without grooves; pubescent (1), or pilose (2). Lemma apex lobed; 3 -fid; incised 0.33–0.3867–0.5 of lemma length; awned; 3 -awned. Principal lemma awn from a sinus. Lateral lemma awns subequal to principal. Palea 1 length of lemma. Palea keels smooth (2), or scaberulous (1). Palea apex dentate (2/2); muticous (2), or with excurrent keel veins (1). Apical sterile florets 1 in number; male (1), or barren (2); lanceolate (2), or ovate (1). Apical sterile lemmas awned.

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp; ellipsoid (1/1).

DISTRIBUTION North America (2), or South America (2).

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