Arthrostylidium excelsum

HABIT Perennial; caespitose. Rhizomes short; pachymorph. Culms leaning; 100–500 cm long; 2–3 mm diam.; woody. Culm-internodes terete; distally glabrous. Lateral branches dendroid. Branch complement two to several; in a clump; subtended by a bare patch above the node; with 1 branch dominant; thinner than stem. Leaf-sheaths glabrous on surface. Leaf-sheath oral hairs setose; 9–17 mm long. Ligule a ciliolate membrane; 0.1–0.2 mm long. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades lanceolate; 10–16 cm long; 14–38 mm wide. Leaf-blade surface glabrous.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; sinuous (distally); bilateral; 9–16 cm long. Spikelet packing broadside to rhachis; distant.

Spikelets appressed, or ascending; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 5–11 fertile florets; with diminished florets at the apex. Spikelets linear; laterally compressed; 25–34 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 3–4 mm long; eventually visible between lemmas; glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume elliptic; 4.5–6 mm long; 0.8–0.9 length of upper glume; chartaceous; without keels; 3 -veined. Lower glume apex acute. Upper glume elliptic; 5.3–6.9 mm long; 0.66–0.75 length of adjacent fertile lemma; without keels; 7 -veined. Upper glume apex acute.

FLORETS Fertile lemma ovate; 8–9.5 mm long; chartaceous; without keel; 9–11 -veined. Lemma surface glabrous, or puberulous. Lemma apex obtuse. Palea 1 length of lemma. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3. Anthers 3; 4.5–5 mm long. Ovary umbonate.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: Mexico. South America: Mesoamericana and Caribbean.

NOTES Bambuseae. Fl Meso-Am 1997.

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