GrassBase - The Online World Grass Flora

Descriptions

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

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

Agrostis mertensii

HABIT Perennial; caespitose. Culms erect, or geniculately ascending; 20–60 cm long. Lateral branches lacking. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane; 1–2 mm long. Leaf-blades flat, or involute; 5–10 cm long; 0.5–3 mm wide. Leaf-blade surface smooth, or scaberulous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; pyramidal; 5–15 cm long. Primary panicle branches spreading; whorled at lower nodes; 1–4 cm long. Panicle axis smooth, or scabrous. Panicle branches smooth, or scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic; laterally compressed; 2.5–3 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus glabrous.

GLUMES Glumes persistent; similar; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume lanceolate; 2.5–3 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 2.5–3 mm long; membranous; 1-keeled; 1 -veined. Upper glume primary vein scaberulous. Upper glume lateral veins absent. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 2–2.5 mm long; hyaline; without keel; 5 -veined. Lemma lateral veins extending close to apex. Lemma apex awned; 1 -awned. Principal lemma awn dorsal; arising 0.5 way up back of lemma; straight, or geniculate; 2–4 mm long overall; without a column, or with twisted column. Palea absent or minute.

FLOWER Lodicules 2; membranous. Anthers 3; 0.75–1.5 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION Europe: northern and eastern. Asia-temperate: Soviet far east and eastern Asia. North America: Subarctic, western Canada, eastern Canada, northwest USA, northeast USA, southwest USA, and southeast USA. South America: western South America and southern South America.

NOTES Aveneae. Man US Gr 1994.

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