Anthoxanthum odoratum L.

sweet vernal grass


Info

Subfamily: Pooideae
Genus etymology: Anthoxanthum = "yellow flower" [Greek} refering to the inflorescence color at maturity
Species etymology: odoratum = "odorous" [Latin] refering to its fragrant hay
Photosynthetic type: C3 (cool season)
Nativity: naturalized - accidental
First recorded in Hawaiʻi: 1907

Map

 Distribution of Anthoxanthum odoratum in Hawaiʻi.
 Distribution of Anthoxanthum odoratum in Hawaiʻi.

Inflorescence

Anthoxanthum odoratum Inflorescence
Anthoxanthum odoratum Inflorescence
Anthoxanthum odoratum Inflorescence
Anthoxanthum odoratum Inflorescence
Anthoxanthum odoratum Inflorescence
Anthoxanthum odoratum Inflorescence

Plant

Anthoxanthum odoratum Plant
Anthoxanthum odoratum Plant
Anthoxanthum odoratum Plant
Anthoxanthum odoratum Plant

Habit

Anthoxanthum odoratum Habit
Anthoxanthum odoratum Habit
Anthoxanthum odoratum Habit
Anthoxanthum odoratum Habit

Spikelets

Anthoxanthum odoratum Spikelets
Anthoxanthum odoratum Spikelets
Anthoxanthum odoratum Spikelets
Anthoxanthum odoratum Spikelets
Anthoxanthum odoratum Spikelets
Anthoxanthum odoratum Spikelets

Landscape

Anthoxanthum odoratum Landscape
Anthoxanthum odoratum Landscape

Description

Plants perennial. Culms (10) 25-60(100) cm, erect, simple or sparingly branched. Auricles 0.5-1 mm, pilose-ciliate, sometimes absent; ligules 2-7 mm, truncate; blades 1-31 cm long, 3-10 mm wide. Panicles (3) 4-14 cm, the spikelets congested; lowermost branches 10-25 mm; pedicels 0.5-1 mm, pubescent. Spikelets 6-10 mm; lower glumes 3-4 mm; upper glumes 8-10 mm; sterile florets 3-4 mm, awn of the first floret 2-4 mm, awn of the second floret 4-9 mm, equaling or only slightly exceeding the upper glumes; bisexual florets 1-2.5 mm; anthers 2, (2.9)3.5-4.8(5.5) mm. 2n = 10,20.
(Description source: Barkworth, M.E., Capels, K.M. & Long, S. (eds.) 1993. Flora of North America, north of Mexico. Volume 24. Magnoliophyta: Commelinidae (in part): Poaceae, Part 1. Oxford University Press, New York. 911 pp. http://floranorthamerica.org/Anthoxanthum_odoratum )

Slender perennials, forming small tufts; culms erect or spreading, 30-60 cm long, ca. 1 mm in diameter, hollow, glabrous, nodes darker than internodes, glabrous. Sheaths 3-8 cm long, striate, shorter than internodes, glabrous or with weak retrorse hairs, ciliate at throat; ligule conspicuous, sometimes purple, membranous, 1.5-4 mm long; blades 5-20 cm long, 2-7 mm wide, glabrous or with scattered weak, soft hairs, conspicuously auriculate. Inflorescence a spike-like, solitary, terminal, cylindrical panicle 3-8 cm long, 0.5-1.5 cm in diameter, peduncle slender, smooth, 10-35 cm long, rachis obscured by the closely imbricate spikelets, the branches very short; spikelets subsessile, lanceoloid, 6.5-10 mm long; glumes membranous, glabrous or with scattered weak hairs, first glume ovate, acute, 3.5-4 mm long, 1-nerved, scabrous on the nerve, second glume ovate, acuminate, 6.5-8.5 mm long, 3-nerved, scabrous on nerves, scaberulous between the nerves; sterile lemmas subequal, oblong, 2.5-3.2 mm long, apex bifid, brownish appressed hirsute, first lemma awned from slightly below apex, the awn straight, ca. 6 mm long, second lemma awned from near base, the awn geniculate, ca. 6 mm long; fertile floret 2-2.5 mm long, enclosed within the 2 sterile lemmas, lemma reddish to dark brown, glossy, broadly ovate, glabrous, acute; palea membranous, narrow, obtuse, ca. 1.5 mm long, wholly enclosed by the lemma. Caryopsis linear, 1.3-2.5 mm long. [2n = 10, 15, 16, 20, 21.]
(Description source: O’Connor, P.J. 1990. Poaceae, pp. 1481–1604. In: Wagner W.L., Herbst D.R. & Sohmer S.H. (eds.)., Manual of the flowering plant of Hawaiʻi. Vol. 2. University of Hawaii Press & Bishop Museum Press, Honolulu )