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flouve odorante, foin d'odeur, large sweet grass, sweet vernal grass, vernal sweetgrass

common sweetgrass, hairy sweetgrass, northern sweet grass, sweetgrass

Habit Plants perennial. Plants perennial; loosely cespitose or the culms solitary, rhizomes elongate, 0.7-2 mm thick.
Culms

(10) 25-60(100) cm, erect, simple or sparingly branched.

40-85(110) cm.

Sheaths

brownish or reddish;

ligules 2.5-5.5 mm;

blades 2.5-5.5 mm wide;

abaxial surfaces glabrous, shiny, adaxial surfaces pilose;

flag leaf blades 1-4.5(6) cm long, 3-4.5 mm wide.

Panicles

(3) 4-14 cm, the spikelets congested;

lowermost branches 10-25 mm;

pedicels 0.5-1 mm, pubescent.

(5)7.5-15 cm long, 2-10 cm wide, open, pyramidal, with 20-100+ spikelets;

branches with 3+ spikelets.

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.

4-6.3 mm, tawny at maturity;

rachilla internodes 0.1-0.3 mm.

Glumes

subequal, exceeding the florets, glabrous, often somewhat purplish;

lowest 2 florets staminate;

lemmas 3-5 mm, with hairs to 0.5 mm towards the apices, margins with 16-30 hairs per mm, hairs 0.5-1 mm, apices acute, emarginate, or bifid;

first lemma 3-5 mm long, 1.1-1.5 mm wide, length usually less than 4 times width, elliptic, awned, awns 0.1-1 mm;

bisexual lemmas 2.9-3.5 mm, hairy distally, hairs 0.5-1 mm, evenly distributed around the apices, bases strongly divergent from the lemma surface;

anthers of staminate florets 1.6-2.1 mm, those of bisexual florets 1.2-1.3 mm.

Auricles

0.5-1 mm, pilose-ciliate, sometimes absent;

ligules 2-7 mm, truncate;

blades 1-31 cm long, 3-10 mm wide.

2n

= 10,20.

= 56.

Anthoxanthum odoratum

Hierochloe hirta ssp. hirta

Distribution
from FNA
AK; AL; AR; CA; CO; CT; DC; DE; GA; ID; IL; IN; KY; LA; MA; MD; ME; MI; MO; MS; NC; NH; NJ; NM; NY; OH; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; HI; BC; LB; NB; NS; ON; PE; QC; Greenland
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Discussion

Anthoxanthum odoratum is native to southern Europe. In the Flora region, it grows in meadows, pastures, grassy beaches, old hay fields, waste places, and openings in coniferous forests, occasionally in dense shade or as a weed in lawns. It is most abundant on the western and eastern sides of the continent, and is almost absent from the central region. In southern British Columbia, it is rapidly invading the moss-covered bedrock of coastal bluffs, and will soon exclude many native species. Diploids (In = 10) have been referred to A. odoratum subsp. alpinum (Á. Löve & D. Love) Hulten. Because the two ploidy levels can be distinguished only through cytological examination (Hedberg 1990), the two subspecies are not recognized here.

Anthoxanthum odoratum was often included in hay and pasture mixes to give fragrance to the hay, but this practice is waning. The aroma is released upon wilting or drying. By itself, the species is unpalatable because of the bitter-tasting coumarin.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Anthoxanthum hirtum is the most widely distributed species of Anthoxanthum in the Flora region, extending from Alaska to northeastern Quebec and south to Washington and Colorado, South Dakota, Illinois, Ohio, and New York. It is not known from Newfoundland or Greenland. Outside the Flora region, it extends from Scandinavia south to Germany and east to Asiatic Russia. It grows in wet meadows and marshes with good water, not in salt- or brackish water. Because much of its native habitat has been drained, it is becoming less common. Its short flag leaf blades and more circular spikelets distinguish it from A. occidentale, and the relative abundance and even distribution of hairs longer than 0.5 mm distinguish it from A. nitens.

Weimark (1971,1987) recognized three subspecies in A. hirtum (which he treated as Hierochloe hirta): subsp. hirta, subsp. arctica G. Weim., and subsp. praetermissa G. Weim. He stated that only H. hirta subsp. arctica grows in North America, but several North American specimens seem to fit within his circumscription of H. hirta subsp. hirta. Because the variation between the two appears continuous, no subspecies of A. hirtum are recognized here.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 24, p. 759. FNA vol. 24, p. 764.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Anthoxanthum Poaceae > subfam. Pooideae > tribe Poeae > Anthoxanthum
Sibling taxa
A. arcticum, A. aristatum, A. hirtum, A. monticola, A. nitens, A. occidentale
A. arcticum, A. aristatum, A. monticola, A. nitens, A. occidentale, A. odoratum
Synonyms A. odoratum subsp. alpinum Hierochloe odorata subsp. hirta, Hierochloe odorata subsp. arctica, Hierochloe hirta subsp. arctica, Hierochloe hirta
Name authority L. (Schrank) Y. Schouten & Veldkamp
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