GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Piresia macrophylla

HABIT Perennial; caespitose. Culms 20–50 cm long; wiry. Leaves cauline; 5–8 per branch. Leaf-sheaths pilose (above). Leaf-sheath oral hairs lacking. Ligule an eciliate membrane. Leaf-blade base with a brief petiole-like connection to sheath; petiole pubescent. Leaf-blades oblong; 9–13 cm long; 15–25 mm wide; mid-green; concolorous. Leaf-blade surface glabrous. Leaf-blade apex acute.

INFLORESCENCE Monoecious; with male and female spikelets in the same inflorescence. Synflorescence on a separate leafless culm. Inflorescence composed of racemes; terminal and axillary.

Racemes 1; single; 2–3 cm long; bearing few fertile spikelets; bearing 4–6 fertile spikelets on each. Rhachis pubescent on surface.

Sexes mixed. Spikelets in pairs. Fertile spikelets pedicelled; 1 in the cluster. Male spikelets sessile; 1 in a cluster. Pedicels cuneate.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 5.5–6 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes deciduous; similar; reaching apex of florets; thinner than fertile lemma. Lower glume elliptic; 5.5–6 mm long; 1 length of upper glume; herbaceous; without keels; 5 -veined. Lower glume lateral veins ribbed; with cross-veins. Lower glume apex acute. Upper glume elliptic; 5.5–6 mm long; 1 length of adjacent fertile lemma; herbaceous; without keels; 3 -veined. Upper glume lateral veins ribbed; with cross-veins. Upper glume apex acute.

FLORETS Fertile florets female. Fertile lemma elliptic; 5.5–6 mm long; indurate; without keel; 5 -veined. Lemma surface pubescent. Lemma margins covering most of palea. Palea indurate; 2 -veined.

FLOWER Anthers 3.

MALE Male spikelets distinct from female; 1 flowered; separately deciduous; lanceolate; 4 mm long. Male spikelet glumes absent. Male spikelet lemma 3 -veined; muticous.

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

NOTES Olyreae. Soderstrom.

ADDITIONAL CHARACTERS Leaf midvein pubescent above.

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