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.

Metcalfia mexicana

HABIT Perennial; caespitose. Basal innovations intravaginal. Culms erect, or geniculately ascending; 70–90 cm long; 0.8–1 mm diam.; 2 -noded. Ligule an eciliate membrane; 2–4 mm long; lacerate. Leaf-blades convolute; 20–40 cm long; 1–2 mm wide. Leaf-blade apex acuminate; pungent.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 12–16 cm long; 1 cm wide. Panicle branches angular; scabrous.

Spikelets in pairs. Fertile spikelets pedicelled; 2 in the cluster. Pedicels angular; unequal; 1.5–15 mm long; scabrous.

FERTILE SPIKELETS Spikelets comprising 3–4 fertile florets; with diminished florets at the apex. Spikelets lanceolate; laterally compressed; 13–16 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pilose; hairy above. Floret callus evident; 1–1.2 mm long; pilose.

GLUMES Glumes persistent; similar; reaching apex of florets. Lower glume lanceolate; 11–14 mm long; 0.9 length of upper glume; membranous; without keels; 7–9 -veined. Lower glume surface asperulous. Lower glume apex acute; awned; 1 -awned. Lower glume awn 1.2–1.6 mm long. Upper glume lanceolate; 12–15 mm long; 1.2–1.5 length of adjacent fertile lemma; membranous; without keels; 7–9 -veined. Upper glume surface asperulous; rough above. Upper glume awned; 1 -awned. Upper glume awn 1.2–1.6 mm long.

FLORETS Fertile lemma ovate; 9–11 mm long; membranous; without keel; 7 -veined. Lemma surface pilose. Lemma hairs 0.6–1 mm long. Lemma apex lobed; 2 -fid; with lanceolate lobes; incised 0.25 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 12–15 mm long overall; with twisted column. Palea lanceolate; 0.75 length of lemma. Palea apex dentate; 2 -fid. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3; 2–2.5 mm long; glabrous. Anthers 2; 1.5–2 mm long. Stigmas 2. Styles free to the base. Ovary pubescent all over.

FRUIT Hilum linear; 0.33 length of caryopsis.

DISTRIBUTION North America: Mexico.

NOTES Duthieeae. WDC.

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