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

foin d'odeur, herbe sainte, hierochloe odorante, manna grass, Mary's grass, sweet grass, vanilla grass, vanilla sweet grass

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.

(5)15-50(90) cm.

Sheaths

brownish or reddish, glabrous or puberulent;

ligules 0.5-6.5(8) mm, truncate, obtuse, or acute;

blades 10-30 cm long, 2-8 mm wide, usually flat, sometimes inrolled, abaxial surfaces glabrous or pubescent, without prominent cross venation, adaxial surfaces glabrous;

flag leaf blades 0.3-1.5(4.5) cm long, 1.5-4.5(6) mm wide.

Panicles

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

lowermost branches 10-25 mm;

pedicels 0.5-1 mm, pubescent.

(2)4-9(12.5) cm long, (1.5)2-5(7) cm wide, open, pyramidal, with 8-100 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.

(2.5)3.5-7.5 mm, mostly tawny, sometimes tinged with green;

rachilla internodes 0.15-0.3 mm, glabrous.

Glumes

subequal, exceeding the florets, glabrous;

lower glumes with lengths 2-5 times widths, usually shorter and wider than the upper glumes;

lowest 2 florets staminate;

lemmas hairy, particularly distally, hairs brown, often papillose-based, to 0.8 mm on the margins and to 0.3 mm near the apices, margins with 11-26 hairs per mm, midvein usually terminating at the apices or extending beyond as an awn, apices acute to rounded, entire or bifid, unawned, mucronate, or with a thin awn, awns to 0.5 mm;

first lemma 3.4-5 mm long, 1-1.5 mm wide, length usually less than 4 times width, elliptic;

bisexual lemmas 2.5-4 mm, usually hairy distally, hairs 0.1-0.5 mm, appressed or almost so at maturity, longer, divergent hairs, if present, concentrated near the midvein;

anthers of staminate florets 0.9-2.3 mm, those of bisexual florets 1.2-1.6 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.

= 28, 42.

Anthoxanthum odoratum

Hierochloe odorata

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
[WildflowerSearch map]
[BONAP county map]
from USDA
[WildflowerSearch map]
[BONAP county map]
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 nitens is primarily a European species. In the Flora region, it grows along the coast from northern Labrador to New England. It is not known from Greenland, although it grows in Iceland and northwestern Europe. It grows in wet meadows and at the edges of sloughs, marshes, roadsides, and fields. Only A. nitens (Weber) Y. Schouten & Veldkamp subsp. nitens is present in the region; it is also present in Europe. It differs from A. nitens subsp. balticum (G. Weim.) G.C. Tucker in being almost always awned and having In = 28.

North American taxonomists have generally interpreted Anthoxanthum nitens as including A. hirtum (and treated both as Hierochloe odorata (L.) Wahlenb.). The two are distinct, although not easy to distinguish. Weimarck (1971) separated the two by the density of the lateral hairs and development of the awns of the staminate florets. The difference in abundance and distribution of hairs more than 0.5 mm long on the apices of the bisexual florets is more reliable, A. nitens having few such long hairs concentrated near the midvein. M.J. Harvey (pers. comm.), who did not distinguish between the two species, found that plants from the Maritime Provinces collected near saltwater were uniformly 2n = 28, whereas those from the interior of New Brunswick westward had 2n = 56. This observation is consistent with Weimark's chromosome counts and distribution maps.

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

Source FNA vol. 24, p. 759. FNA vol. 24, p. 762.
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. hirtum, A. monticola, A. occidentale, A. odoratum
Synonyms A. odoratum subsp. alpinum Hierochloe odorata, Hierochloe borealis
Name authority L. (Weber) Y. Schouten & Veldkamp
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