Aristida appressa

HABIT Perennial; caespitose. Butt sheaths persistent and investing base of culm; with curly dead sheaths. Culms 30–60 cm long. Leaf-sheaths glabrous on surface. Ligule a fringe of hairs. Leaf-blades flat, or involute; 10–35 cm long; 1–4 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; equilateral, or nodding; 10–25 cm long. Primary panicle branches appressed, or ascending; 2–10 cm long.

Spikelets appressed; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 12–14 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent; obtuse.

GLUMES Glumes similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 9–11 mm long; 0.75 length of upper glume; membranous; 1 -veined. Lower glume lateral veins absent. Lower glume apex setaceously attenuate; muticous, or awned; 1 -awned. Lower glume awn 1–2 mm long. Upper glume lanceolate; 12–14 mm long; 1.2–1.5 length of adjacent fertile lemma; membranous; 1 -veined. Upper glume lateral veins absent. Upper glume apex setaceously attenuate; muticous, or awned; 1 -awned. Upper glume awn 1–2 mm long.

FLORETS Fertile lemma linear; subterete; 8–12 mm long; coriaceous; without keel; 3 -veined. Lemma margins convolute; covering most of palea. Lemma apex awned; 3 -awned. Principal lemma awn 3-branched; with 15–22 mm long limb; with twisted column. Column of lemma awn (2–)4–8 mm long. Lateral lemma awns 15–22 mm long; subequal to principal.

FLOWER Anthers 3.

DISTRIBUTION North America: Mexico. South America: Mesoamericana.

NOTES Aristideae. Fl Nov Gal 1994.

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