Burke: Poa lettermanii vs. Poa bulbosa

	Poa lettermanii	Poa bulbosa
	Letterman's blue grass	bulbous bluegrass
Habit		Strongly tufted, glabrous perennial, the culms hollow, 1.5-4 dm. tall.
Leaves		Sheaths open almost to the base; ligules 1.5-3 mm. long, blunt to acuminate, usually entire; blades 1-2.5 mm. broad, flat to folded, scabrous, the tip prow-like.
Flowers		Inflorescence an open to contracted panicle up to 10 cm. long; spikelets 3-5 mm. long, but florets usually modified into elongate, purplish bulbils up to 20 mm. long; glumes 2-3 mm. long; normal lemmas about 5 per spikelet, keeled, 2-4 mm. long, webbed at base; viviparous spikelets modified into a single bulbil enclosed by the several leaf-like lemmas 5-20 mm. long; stamens and pistils mostly lacking.

	Poa lettermanii	Poa bulbosa
Flowering time	July-September	March-June
Habitat	Mesic to wet, rocky, alpine slopes	Disturbed areas from the coast to midmontane.
Distribution	Occurring in the Cascades Range in Washington; British Columbia to California, east to the Rocky Mountains. [WildflowerSearch map] [BONAP county map]	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]
Origin	Native	Introduced
Conservation status	Not of concern	Not of concern
Sibling taxa	P. alpina, P. annua, P. arctica, P. bolanderi, P. bulbosa, P. compressa, P. confinis, P. curtifolia, P. cusickii, P. fendleriana, P. glauca, P. howellii, P. infirma, P. interior, P. laxiflora, P. leibergii, P. leptocoma, P. macrantha, P. marcida, P. ×multnomae, P. nemoralis, P. nervosa, P. palustris, P. paucispicula, P. pratensis, P. secunda, P. stenantha, P. suksdorfii, P. trivialis, P. unilateralis, P. wheeleri	P. alpina, P. annua, P. arctica, P. bolanderi, P. compressa, P. confinis, P. curtifolia, P. cusickii, P. fendleriana, P. glauca, P. howellii, P. infirma, P. interior, P. laxiflora, P. leibergii, P. leptocoma, P. lettermanii, P. macrantha, P. marcida, P. ×multnomae, P. nemoralis, P. nervosa, P. palustris, P. paucispicula, P. pratensis, P. secunda, P. stenantha, P. suksdorfii, P. trivialis, P. unilateralis, P. wheeleri
Subordinate taxa		P. bulbosa ssp. vivipara
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Poa bulbosa

Letterman's blue grass

bulbous bluegrass

Habit

Strongly tufted, glabrous perennial, the culms hollow, 1.5-4 dm. tall.

Leaves

Sheaths open almost to the base;

ligules 1.5-3 mm. long, blunt to acuminate, usually entire;

blades 1-2.5 mm. broad, flat to folded, scabrous, the tip prow-like.

Flowers

Inflorescence an open to contracted panicle up to 10 cm. long;

spikelets 3-5 mm. long, but florets usually modified into elongate, purplish bulbils up to 20 mm. long;

glumes 2-3 mm. long; normal lemmas about 5 per spikelet, keeled, 2-4 mm. long, webbed at base; viviparous spikelets modified into a single bulbil enclosed by the several leaf-like lemmas 5-20 mm. long;

stamens and pistils mostly lacking.