Guadua chacoensis

HABIT Perennial; caespitose. Rhizomes short; pachymorph. Culms erect; inclined at the tip; 1000–2000 cm long; 8–15 mm diam.; woody; with root thorns from the nodes. Culm-internodes semiterete; hollow; mid-green. Lateral branches dendroid; intravaginal. Bud complement 1. Branch complement three, or several; thinner than stem. Culm-sheaths deciduous; 20–50 cm long; 1.7–2.5 times as long as wide; glabrous, or hispid; with tawny hairs; truncate at apex; without auricles; glabrous on shoulders. Culm-sheath ligule 0.8–1 mm high; ciliolate. Culm-sheath blade triangular; as wide as sheath at base; demarcated but persistent; erect; 4–13 cm long; 30–80 mm wide; glabrous on surface, or pubescent and with ciliate margins; acute. Leaves 7–9 per branch. Leaf-sheaths glabrous on surface; outer margin hairy. Leaf-sheath oral hairs ciliate; curly; 2–3 mm long; pale. Ligule a ciliolate membrane; 0.2–0.4 mm long; pubescent on abaxial surface. Leaf-blade base with a brief petiole-like connection to sheath; petiole 0.2–0.3 cm long; petiole glabrous. Leaf-blades lanceolate; 10–24 cm long; 5–25 mm wide. Leaf-blade venation with 8–14 secondary veins. Leaf-blade surface glabrous, or hispid; sparsely hairy; hairy adaxially. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Synflorescence bractiferous; paniculate; 30–40 cm long; open; with glumaceous subtending bracts; bracts 8–10 mm long; with axillary buds at base of spikelet; prophyllate below lateral spikelets.

Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1–2 basal sterile florets; 2–4 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 20–50 mm long; 4–5 mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 5–7 mm long; obscured by lemmas; pubescent.

GLUMES Glumes several; 1–2 empty glumes; persistent; similar; shorter than spikelet. Upper glume ovate; 5–8 mm long; without keels; 7–9 -veined. Upper glume apex acute; mucronate.

FLORETS Basal sterile florets similar; barren; without significant palea; persisting on inflorescence. Lemma of lower sterile floret similar to upper glume; ovate; 10–14 mm long; puberulous; obtuse; mucronate. Fertile lemma ovate; 12–16 mm long; 7–12 mm wide; coriaceous; shiny; without keel; 12–17 -veined. Lemma surface puberulous; hairy below. Lemma margins convolute; covering most of palea. Lemma apex obtuse; mucronate, or awned. Principal lemma awn 0.8–1 mm long overall. Palea 6–14 mm long; 11 -veined. Palea keels winged; conspicuously winged. Palea surface pubescent. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3; 3–5 mm long; veined; ciliate. Anthers 6; 5–8 mm long; anther tip apiculate. Stigmas 3.

FRUIT Caryopsis with adherent pericarp; fusiform; 9–12 mm long; light brown. Embryo 0.5 length of caryopsis.

DISTRIBUTION South America: western South America, Brazil, and southern South America.

NOTES Bambuseae. Lond & Pet 1996.

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