Flora of North America species comparison

Phleum alpinum grows along stream banks, on moist prairie hillsides, and in wet mountain meadows. It is a circumboreal species extending, in the Flora region, from northern North America southward through the mountains to Mexico and South America. It is also widespread in northern Eurasia. Isolated, depauperate plants of P. pratense may be difficult to distinguish from P. alpinum; there is never any difficulty in the field.

Kula et al. (2006) demonstrated that American and northern European plants of Phleum alpinum belong to the same taxon. They mistakenly identified the taxon as P. commutatum Gaudin. Because Humphries (1978) lectotypified P. alpinum on a plant from Lapland, it has priority over P. commutatum. North American plants belong to P. alpinum L. subsp. alpinum and are tetraploid. The count of 2n =14 applies to Phleum alpinum subsp. rhaeticum Humphries, which grows in the mountains of central and southern Europe.

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

Phleum is a genus of approximately 15 species, most of which are native to Eurasia. One species, P. alpinum, is native to the Flora region and six are introduced. One of the introduced species, P. pratense, has been established in the region for a long time. It is also widely cultivated as a fodder grass, both in the Flora region and in other parts of the world. Phleum phleoides was first recognized as being present in the Flora region in 1990. Phleum exaratum has been reported from the United States. No specimens supporting the report have been seen. It resembles P. arenarium (p. 675), but has anthers 1.5-2 mm long rather than 0.3-1.2 mm, and an inflorescence that is rounded at the base.

Species of Phleum are sometimes mistaken for Alopecurus, but Alopecurus has obtuse to acute glumes that are unawned or taper into an awn, lemmas that are both awned and keeled, and paleas that are absent or greatly reduced. The species of Phleum that are most abundant in the Flora region are easily recognized by their strongly ciliate, abruptly truncate, awned glumes and adnate panicle branches. In addition, in Phleum the lemmas are not keeled, and the paleas are always subequal to the lemmas.

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