GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Polytoca digitata

HABIT Perennial. Butt sheaths persistent and investing base of culm; with compacted dead sheaths. Culms 100–150 cm long. Culm-nodes pubescent. Ligule a ciliolate membrane. Leaf-blades 45–60 cm long; 15–25 mm wide. Leaf-blade surface glabrous, or hirsute.

INFLORESCENCE Monoecious; with male terminal and mixed axillary inflorescences. Inflorescence composed of racemes; axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole lanceolate; herbaceous.

Racemes 1; single; 3–8 cm long; bearing few fertile spikelets; bearing 3–6 fertile spikelets on each (and 0–10 male spikelets). Rhachis fragile at the nodes; subterete; pilose on surface. Rhachis internodes oblong; bearing a sterile companion laterally. Rhachis internode tip cupuliform.

Sexes segregated; on bisexual branches; with male above. Spikelets embracing internode; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Male spikelets sessile and pedicelled; 2 in a cluster. Pedicels fused to internode; united wholly.

STERILE SPIKELETS Companion sterile spikelets represented by single glumes; lanceolate; 12–18 mm long; longer than fertile; separately deciduous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 6–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus base truncate; with central peg; attached transversely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume elliptic; 1 length of spikelet; indurate; much thinner above; pallid; 2-keeled; keeled above; winged on keel; winged above. Lower glume surface not waisted; villous; hairy below. Lower glume apex entire; obtuse. Upper glume elliptic; coriaceous. Upper glume apex acuminate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; cartilaginous; acuminate. Fertile florets female. Fertile lemma oblong; hyaline; without keel. Lemma apex acuminate. Palea hyaline; without keels.

FRUIT Caryopsis with adherent pericarp; 7–8 mm long. Hilum punctiform.

MALE Male inflorescence of subdigitate racemes. Male spikelets distinct from female; with pedicels fused to rhachis; 6–7 mm long. Male spikelet glumes 2; muticous.

DISTRIBUTION Asia-temperate: China. Asia-tropical: India, Indo-China, Malesia, and Papuasia.

NOTES Andropogoneae. Bor.


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