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.

Isachne arundinacea

HABIT Perennial. Rootstock evident. Culms rambling; 100–500 cm long; 4–8 mm diam.; woody; rooting from lower nodes. Culm-internodes with small lumen; distally glabrous. Lateral branches ample. Leaf-sheaths glabrous on surface; outer margin hairy. Ligule a fringe of hairs; 0.5–3.5 mm long. Leaf-blades linear, or lanceolate; 9–20 cm long; 7–22 mm wide. Leaf-blade surface scabrous; glabrous, or hispid; hairy abaxially, or on both sides.

INFLORESCENCE Inflorescence a panicle. Peduncle 4–11 cm long; glabrous.

Panicle open; ovate; 8–12 cm long; 8–11 cm wide; with spikelets clustered towards branch tips. Primary panicle branches spreading.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2 fertile florets; without rhachilla extension. Spikelets orbicular, or obovate; subterete; 1.4–1.8 mm long; breaking up at maturity; disarticulating above glumes but not between florets.

GLUMES Glumes deciduous; similar; with lower narrower than upper; shorter than spikelet, or reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 1–1.4 mm long; 0.75 length of spikelet; membranous; without keels; 5 -veined. Lower glume surface glabrous, or pubescent; hairy at apex. Lower glume apex obtuse. Upper glume ovate; 1–1.7 mm long; 0.9–1 length of spikelet; membranous; without keels; 7 -veined. Upper glume surface glabrous, or pubescent; hairy at apex. Upper glume apex obtuse.

FLORETS Fertile florets with the lowest dissimilar. Lowest fertile lemma 1.4–1.7 mm long; of similar consistency to adjacent lemma. Fertile lemma elliptic, or obovate; 1–1.3 mm long; coriaceous; without keel. Lemma margins involute. Lemma apex obtuse. Palea coriaceous; 2 -veined.

FLOWER Anthers 2–3; 1 mm long; yellow, or purple.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: Mexico. South America: Mesoamericana, Caribbean, northern South America, and western South America.

NOTES Isachneae. Fl Costa Rica 1994.

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