Guadua Chacoensis

HABIT:

• Perennial; caespitose. Rhizomes short; pachymorph.
• Culms erect; inclined at the tip; 1000–2000 cm long; 80–150 mm diam.; woody; with root thorns from the nodes.
• Culm-internodes semiterete; thin-walled; 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:

• 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:

• Argentina
• Bolivia
• Paraguay

 

Sources:
GrassBase - The Online World Grass Flora
INBAR (International Network for Bamboo and Rattan)