Muhlenbergia tenella

HABIT Annual; caespitose. Culms geniculately ascending, or decumbent; 15–35 cm long; 0.2–0.3 mm diam. Culm-internodes distally glabrous. Culm-nodes glabrous. Lateral branches ample; arising from lower culm and mid culm. Leaf-sheaths glabrous on surface, or hirsute. Ligule an eciliate membrane; 0.3 mm long; lacerate. Leaf-blades 2–3.5 cm long; 0.8–2 mm wide. Leaf-blade surface glabrous, or pubescent; hairy on both sides.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 3–7 cm long. Primary panicle branches appressed; 1 -nate; bearing spikelets almost to the base.

Spikelets appressed; solitary. Fertile spikelets pedicelled. Pedicels 1–3 mm long.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 2.2–2.7 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 0.6–1.7 mm long; 0.33 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate, or setaceously attenuate. Upper glume lanceolate; 0.9–1.7 mm long; 0.5 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate, or setaceously attenuate.

FLORETS Fertile lemma lanceolate; 1.8–2.7 mm long; membranous; without keel; 3 -veined. Lemma lateral veins prominent. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn flexuous; 15–25 mm long overall. Palea 1 length of lemma; 2 -veined.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 0.3–0.4 mm long; yellow.

FRUIT Caryopsis with adherent pericarp; fusiform.

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

NOTES Eragrostideae. Fl Costa Rica 1994.

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