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.

Chasmanthium ornithorhynchum

HABIT Perennial; caespitose. Rhizomes short; knotty. Culms 50–85 cm long; 0.5 mm diam. Lateral branches lacking, or sparse. Leaf-sheaths glabrous on surface; outer margin hairy. Ligule a ciliolate membrane. Collar pubescent. Leaf-blades 6–13 cm long; 3–7 mm wide. Leaf-blade margins ciliate; hairy at base.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; 3–10 cm long. Primary panicle branches 2–4 cm long; bearing 4–7 fertile spikelets on each lower branch. Panicle axis glabrous, or pilose. Panicle branches pubescent in axils.

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 2–4 basal sterile florets; 2–3 fertile florets; with diminished florets at the apex. Spikelets obovate; laterally compressed; (4–)7–12 mm long; 11–17 mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes definite.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume ovate; 2–3 mm long; 1 length of upper glume; herbaceous; 1-keeled. Lower glume apex acuminate. Upper glume ovate; 2–3 mm long; 0.33–0.5 length of adjacent fertile lemma; herbaceous; 1-keeled. Upper glume apex acuminate.

FLORETS Basal sterile florets similar; barren; without significant palea; persisting on inflorescence. Lemma of lower sterile floret similar to fertile lemma; ovate; 3–5 mm long; herbaceous; 1-keeled; acute. Fertile florets increasing in size upwards. Fertile lemma ovate; 4–7 mm long; herbaceous; keeled; 11–13 -veined. Lemma midvein scabrous. Lemma apex acuminate. Palea 1 length of lemma; 2 -veined. Palea keels winged; narrowly winged. Apical sterile florets distinct from fertile.

FLOWER Lodicules 2; cuneate; fleshy. Anthers yellow.

FRUIT Caryopsis with adherent pericarp; ovoid; laterally compressed; exposed between gaping lemma and palea at maturity; 2–3 mm long; dark brown.

DISTRIBUTION North America: southeast USA.

NOTES Centotheceae. Yates 1998.

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