|
Note - this takes you off
of our website |
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.
Streptogyna americana
HABIT Perennial; caespitose. Rhizomes absent. Culms erect; 60–150 cm long. Ligule an eciliate membrane; 1–2 mm long; pubescent on abaxial surface; erose. Leaf-blade base with a false petiole. Leaf-blades lanceolate; 30–60 cm long; 8–16(–24) mm wide. Leaf-blade venation with distinct cross veins. Leaf-blade apex acuminate.
INFLORESCENCE Inflorescence composed of racemes.
Racemes 1; single; unilateral; 15–50 cm long. Rhachis semiterete; pubescent on surface. Spikelet packing broadside to rhachis; regular; 1 -rowed.
Spikelets appressed; solitary. Fertile spikelets pedicelled. Pedicels 1–2 mm long.
FERTILE SPIKELETS Spikelets comprising 2–4 fertile florets; with diminished florets at the apex. Spikelets linear, or oblong; laterally compressed; 20–30 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes terete; springy and forming a hair trap; 3–5 mm long; eventually visible between lemmas. Floret callus elongated; glabrous; obtuse.
GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 3–10 mm long; 0.2–0.5 length of upper glume; scarious; dark brown; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume lanceolate; 17–23 mm long; 1 length of adjacent fertile lemma; scarious; dark brown; 1-keeled; 9 -veined. Upper glume lateral veins with cross-veins. Upper glume apex acute; mucronate.
FLORETS Fertile lemma oblong; subterete; 18–22 mm long; coriaceous; dark brown; without keel; 9 -veined. Lemma surface glabrous. Lemma margins convolute; covering most of palea. Lemma apex dentate; truncate; awned; 1 -awned. Principal lemma awn from a sinus; 15–25 mm long overall; limb scaberulous. Palea keels contiguous above a sulcus. Apical sterile florets resembling fertile though underdeveloped.
FLOWER Lodicules 3; oblanceolate; 1.5–2.5 mm long; membranous; veined; ciliate; obtuse. Anthers 2. Stigmas 3; terminally exserted and tangled; papillose. Ovary glabrous.
FRUIT Caryopsis with adherent pericarp; linear; isodiametric; biconvex; 15 mm long; glabrous; apex rostrate. Embryo 0.1 length of caryopsis. Hilum linear; 1 length of caryopsis.
DISTRIBUTION North America: Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, and Brazil.
NOTES Streptogyneae. WDC.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
