Anthoxanthum aristatum

HABIT Annual; caespitose. Butt sheaths herbaceous; withering. Culms erect, or geniculately ascending; 10–40 cm long; 4–5 -noded. Lateral branches sparse. Leaves mostly basal. Ligule an eciliate membrane; 1.5–3 mm long. Leaf-blades 0.8–6 cm long; 1–5 mm wide; aromatic. Leaf-blade surface glabrous, or pubescent; hairy adaxially. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; oblong, or ovate; continuous, or interrupted; 1–4 cm long; 0.3–1.2 cm wide.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels oblong; 0.1–0.3 mm long; pubescent.

FERTILE SPIKELETS Spikelets comprising 2 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 5–7.5(–8) mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; dissimilar; exceeding apex of florets; thinner than fertile lemma; shiny. Lower glume ovate; 3.6–5.2 mm long; 0.5–0.6 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume surface glabrous. Lower glume apex acuminate; muticous, or mucronate. Upper glume elliptic; 5–7.5(–8) mm long; 2.5–4 length of adjacent fertile lemma; membranous; with hyaline margins; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume surface glabrous. Upper glume apex acuminate; muticous, or mucronate.

FLORETS Basal sterile florets dissimilar; barren; without significant palea; attached to and deciduous with the fertile. Lemma of lower sterile floret oblong; 2.8–3.9 mm long; 1.5–2 length of fertile lemma; membranous; 1-keeled; 4–5 -veined; pilose; erose; truncate; awned. Awn of lower sterile floret dorsal; arising 0.6 way up back of lemma; 4–5 mm long. Lemma of upper sterile floret oblong; 3–4 mm long; 1 length of lower sterile floret; membranous; pilose; erose; truncate; awned. Awn of upper sterile floret dorsal; arising 0.1 way up back of lemma; geniculate; 7–10 mm long. Fertile lemma orbicular; (1.4–)1.6–2.1 mm long; cartilaginous; shiny; without keel; 5 -veined. Lemma lateral veins obscure. Lemma margins convolute; covering most of palea. Lemma apex obtuse. Palea oblong; 1 length of lemma; 1 -veined; without keels.

FLOWER Lodicules absent. Anthers 2; 2.8–4.1 mm long. Stigmas 2; protogynous; pubescent.

FRUIT Caryopsis with adherent pericarp; ellipsoid. Embryo 0.33 length of caryopsis. Hilum punctiform.

DISTRIBUTION Europe: northern, central, southwestern, southeastern, and eastern. Africa: Macaronesia. Asia-temperate: western Asia. Australasia: Australia and New Zealand. North America: western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, and southeast USA.

NOTES Aveneae. TAC.

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