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blue bunchgrass, blue fescue, bluebunch fescue, Idaho fescue

western fescue

Habit Plants densely cespitose, without rhizomes. Plants densely to loosely cespitose, without rhizomes.
Culms

25-85 (100) cm, usually smooth, glabrous, occasionally scabrous below the inflorescences.

(25)40-80(110) cm, glabrous, smooth.

Sheaths

closed for less than 1/2 their length, smooth or scabrous, rarely pilose, persistent;

collars glabrous;

ligules 0.2-0.6 mm;

blades (0.3)0.5-0.9(1.5) mm in diameter, conduplicate, abaxial surfaces smooth or scabrous, adaxial surfaces scabrous or pubescent, rarely pilose, often glaucous or bluish, veins (3)5(7), ribs (1)3-5, well defined;

abaxial sclerenchyma in 5-7 wide, irregular strands;

adaxial sclerenchyma absent.

closed for much less than 1/2 their length, glabrous, somewhat persistent or slowly shredding into fibers;

collars glabrous;

ligules 0.1-0.4 mm, usually longer at the sides;

blades all alike, 0.3-0.7 mm in diameter, conduplicate, abaxial surfaces smooth or scabridulous, veins (3)5, ribs 1-5;

abaxial sclerenchyma in 5-7 narrow strands, about as wide as the adjacent veins;

adaxial sclerenchyma absent.

Inflorescences

(5)7-15(20) cm, loosely contracted or open, with 1-2 branches per node;

branches usually somewhat spreading at maturity, sometimes erect, rarely reflexed, lower branches with 2+ spikelets.

(5)10-20 cm, open, with 1-2 branches per node;

branches 1-15 cm, lax, widely spreading to reflexed, lower branches usually reflexed at maturity, with 2+ spikelets.

Spikelets

(5.8) 7.5-13.5(19) mm, with (2)4-7(9) florets.

6-12 mm, with 3-6(7) florets.

Glumes

exceeded by the upper florets, ovate-lanceolate to lanceolate, mostly smooth, sometimes scabrous distally;

lower glumes 2.4-5(6) mm;

upper glumes 3-6(8) mm;

lemmas 5-8.5(10) mm, scabrous at the apices, awns (1.5)3-6(7) mm, usually more than 1/2 as long as the lemma bodies;

paleas shorter than to about as long as the lemmas, intercostal region scabrous or puberulent distally;

anthers 2.4-4.5 mm;

ovary apices glabrous.

exceeded by the upper florets, ovate to ovate-lanceolate, glabrous and smooth or slightly scabrous;

lower glumes 2-5 mm;

upper glumes 3-6 mm;

lemmas (4)4.5-6.5(8) mm, ovate-lanceolate to attenuate, glabrous or finely puberulent, awns 3-12 mm, usually longer than the lemma bodies;

paleas slightly shorter than the lemmas, intercostal region scabrous or puberulent distally;

anthers (1)1.5-2(3) mm;

ovary apices densely pubescent.

2n

= 28.

= 28 [other numbers have been reported for this species, but are probably based on misidentifications].

Festuca idahoensis

Festuca occidentalis

Distribution
from FNA
AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; ID; MI; MT; OR; SD; UT; WA; WI; WY; AB; BC; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

Festuca idahoensis grows in grasslands, open forests, and sagebrush meadow communities, mostly east of the Cascade Mountains, from southern British Columbia eastward to southwestern Saskatchewan and southward to central California and New Mexico. It extends up to 3000 m in the southern part of its range. It is often a dominant plant, and provides good forage. The young foliage is particularly palatable.

Festuca idahoensis differs from F. arizonica (see previous), with which it is sometimes confused, in its less prominently ribbed blades and glabrous ovary apices. It has frequently been included in F. ovina (p. 422).

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

Festuca occidentalis grows in dry to moist, open woodlands, forest openings, and rocky slopes, up to 3100 m. It extends from southern Alaska and northern British Columbia to southwestern Alberta, south to southern California and eastward to Wyoming, and, as a disjunct, around the upper Great Lakes in Ontario, eastern Wisconsin, and Michigan. It is sometimes important as a forage grass, but is usually not sufficiently abundant.

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

Source FNA vol. 24, p. 438. FNA vol. 24, p. 437.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Festuca > subg. Festuca > sect. Festuca Poaceae > subfam. Pooideae > tribe Poeae > Festuca > subg. Festuca > sect. Festuca
Sibling taxa
F. altaica, F. amethystina, F. arizonica, F. auriculata, F. baffinensis, F. brachyphylla, F. brevissima, F. californica, F. calligera, F. campestris, F. dasyclada, F. earlei, F. edlundiae, F. elmeri, F. filiformis, F. frederikseniae, F. glauca, F. groenlandica, F. hallii, F. heterophylla, F. hyperborea, F. lenensis, F. ligulata, F. minutiflora, F. occidentalis, F. ovina, F. paradoxa, F. prolifera, F. pseudovivipara, F. roemeri, F. rubra, F. saximontana, F. sororia, F. subulata, F. subuliflora, F. subverticillata, F. thurberi, F. trachyphylla, F. valesiaca, F. versuta, F. viridula, F. viviparoidea, F. washingtonica
F. altaica, F. amethystina, F. arizonica, F. auriculata, F. baffinensis, F. brachyphylla, F. brevissima, F. californica, F. calligera, F. campestris, F. dasyclada, F. earlei, F. edlundiae, F. elmeri, F. filiformis, F. frederikseniae, F. glauca, F. groenlandica, F. hallii, F. heterophylla, F. hyperborea, F. idahoensis, F. lenensis, F. ligulata, F. minutiflora, F. ovina, F. paradoxa, F. prolifera, F. pseudovivipara, F. roemeri, F. rubra, F. saximontana, F. sororia, F. subulata, F. subuliflora, F. subverticillata, F. thurberi, F. trachyphylla, F. valesiaca, F. versuta, F. viridula, F. viviparoidea, F. washingtonica
Synonyms F. idahoensis var. oregona
Name authority Elmer Hook.
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