Nassella mexicana

HABIT Perennial; caespitose. Culms geniculately ascending, or decumbent; 20–30 cm long. Leaf-sheaths glabrous on surface. Leaf-sheath oral hairs lacking. Ligule an eciliate membrane. Leaf-blades filiform; involute; 5–20 cm long; 0.2–0.3 mm wide. Leaf-blade surface scabrous; rough adaxially. Leaf-blade apex pungent.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear; 5–10 cm long. Primary panicle branches appressed, or ascending.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 10 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; pubescent (white); obtuse.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 1 length of upper glume; membranous; without keels; 3 -veined. Lower glume apex acute. Upper glume lanceolate; 10 mm long; membranous; without keels; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma oblong; subterete; 4 mm long; coriaceous; dark brown; without keel; 5 -veined. Lemma surface pubescent; hairy all along. Lemma margins convolute; covering most of palea. Lemma apex surmounted by a ring of hairs; with this appendage 0.5 mm long; awned; 1 -awned. Principal lemma awn bigeniculate; 10 mm long overall; with a straight or slightly twisted column. Column of lemma awn puberulous. Palea 2 -veined; without keels.

FLOWER Lodicules 3. Anthers 3. Stigmas 2. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

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

NOTES Stipeae. N Amer Fl 1994.

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