Panicum piauiense

HABIT Perennial; caespitose. Roots bearing tubers. Cataphylls evident. Rhizomes short. Butt sheaths woolly. Glands sunken crateriform. Culms erect; 40–80 cm long. Culm-internodes terete; distally glabrous, or pilose. Culm-nodes constricted; brown; pubescent. Lateral branches ample. Leaf-sheaths 4–6 cm long; longer than adjacent culm internode; glabrous on surface, or pilose; outer margin hairy. Ligule a ciliate membrane; 0.5 mm long; glabrous on abaxial surface, or ciliate from base of abaxial surface. Collar pubescent. Leaf-blade base cordate; with a brief petiole-like connection to sheath; petiole pubescent. Leaf-blades lanceolate; 9–13 cm long; 10–15 mm wide. Leaf-blade surface scabrous; rough on both sides; glabrous, or hirsute; densely hairy; hairy on both sides. Leaf-blade margins cartilaginous; scaberulous; glabrous, or ciliate; hairy at base. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 20–30; borne along a central axis; ascending; unilateral; 1–3 cm long; simple, or secondarily branched. Central inflorescence axis 7–22 cm long; hispid. Rhachis angular; with scattered hairs; scabrous on margins. Raceme-bases hirsute.

Spikelets in pairs. Fertile spikelets sessile and pedicelled. Pedicels scabrous; glabrous, or ciliate.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 2.4–2.8 mm long; 0.8 mm wide; falling entire.

GLUMES Glumes similar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 1.8–2.5 mm long; 0.5–0.75 length of spikelet; membranous; without keels; 3 -veined. Lower glume primary vein scabrous. Lower glume inner surface pubescent. Lower glume apex acuminate. Upper glume ovate; 2.3–2.7 mm long; 1 length of spikelet; membranous; without keels; 5 -veined. Upper glume primary vein scabrous. Upper glume surface scabrous; glabrous, or pilose; inner surface pubescent. Upper glume margins ciliate. Upper glume apex acute, or acuminate.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret similar to upper glume; ovate; 2.3–2.6 mm long; 1 length of spikelet; membranous; eglandular, or glandular (2–4 glands); 5 -veined; scabrous; glabrous, or pilose; ciliate on margins; acute. Palea of lower sterile floret 1.7–2 mm long. Fertile lemma lanceolate; dorsally compressed; 1.7–2 mm long; indurate; yellow; without keel. Lemma margins involute. Palea involute; indurate.

FRUIT Caryopsis with adherent pericarp; ellipsoid; 1.3 mm long. Hilum elliptic.

DISTRIBUTION South America: Brazil.

NOTES Paniceae. Zuloaga 1996.

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