lysandra's Identifications

Poa alpina in Big Sky is found in recent roadside plantings, attesting to its ecological ability to withstand some level of disturbance and serve as a reclamation and restoration species. The broad but short basal leaves (e.g., about 4-5 mm wide and usually less than about 4-5 cm long) and pyramidal panicles bearing broad spikelets are diagnostic of this montane bluegrass.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157686910699350/

The pyramidal panicle, broad basal leaves (e.g., 3-5 mm wide), and lemmas that are strongly keeled and with a conspicuously hairy back distinguish this usually alpine to subalpine bunchgrass.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157686910699350/

Poa alpina is especially common along roadsides and margins of parking lots at upper elevations in the Beartooth Mountains. This suggests that this bunchgrass has an excellent ecological ability to withstand some level of disturbance and serve as a reclamation and restoration species. The broad but short basal leaves (e.g., about 4-5 mm wide and usually less than about 4-5 cm long) and pyramidal panicles bearing broad spikelets are diagnostic of this montane bluegrass.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157686910699350/

The distinguishing features of this grass are its perennial bunched habit with few old leaves remaining during the current year, the new leaves with a prow-tip and broad (up to 5 mm wide), and the pyramidal inflorescence that bears spikelets, which have hairy lemmas backs.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157686910699350/

The small bunches with broad greenish leaf blades (e.g., over 3 mm wide) and inflorescences that readily turn brown by late summer are distinctive of this species.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157686910699350/

The annual habit, short inflorescence, and lemmas that are distinctly widest at mid-length distinguish this species.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157689275854286/

The alpine grass with a spreading (rhizomatous) growth form is distinguished by its ligules that are typically 3-6 mm long, pyramidal inflorescence, and large spikelets (5-8 mm long) that comprise hairy florets, each of which is 4-6 mm long and produces hairs that are often cobwebby. The lemma hairs are typically very conspicuous from side view of the undissected spikelet.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157685846073812/

Poa compressa is the grass with green stems. This rhizomatous bluegrass is common along roadside ditches and not so much up on the road cut. The spreading rhizomatous habit is not obscured because of the production of few if any basal leaves and relatively short stem leaves (e.g., generally 3-4 mm long). This roadside site also includes an abundance of quackgrass and Canada wildrye.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157685609847643/

The panicles are typically narrow and bear relatively few small spikelets. This site is along the Middle Cottonwood trail, central west Bridger Range.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/sets/72157685609847643/

Absence of a basal leaf bunch, short stature (often less than 30 cm tall), open panicles of small spikelets, each spikelet usually 3-4 mm long, and subalpine to alpine habit usually on windswept slopes and rocky outcrops combine to distinguish this bunchgrass. This site is at the head of Big Timber Canyon.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/albums/72157686878996731

A subalpine to alpine species with an open panicle (at maturity) and leafy stems that lack a basal leaf bunch. This site is at the south end of the Bridger Range on Baldy Mountain.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/albums/72157686878996731

The leaves mostly from the stem rather than basal and the small few-floreted spikelets held in an open panicle similar to that of Agrostis stolonifera (redtop) are distinctive of this species and very similar to the traits of Poa palustris (fowl bluegrass). Inland bluegrass differs from fowl bluegrass mainly by its shorter stature (e.g., usually less than 40 cm tall) and higher elevation more xeric setting. This site is on the ridge line above Bridger Bowl, Bridger Range.

Photo documentation and species diagnosis at https://www.flickr.com/photos/plant_diversity/albums/72157686878996731