Flora of North America species comparison

Bromus tectorum is a European species that is well established in the Flora region and other parts of the world. It grows in disturbed sites, such as overgrazed rangelands, fields, sand dunes, road verges, and waste places. In the southwestern United States, Bromus tectorum is considered a good source of spring feed for cattle, at least until the awns mature. It is highly competitive and dominates rapidly after fire, especially in sagebrush areas. The resulting dense, fine fuels permanently shorten the fire-return interval, further hindering reestablishment of native species. It now dominates large areas of the sagebrush ecosystem of the western Flora region.

Specimens with glabrous spikelets have been called Bromus tectorum f. nudus (Klett & Richt.) H. St. John. They occur throughout the range of the species, and are not known to have any other distinguishing characteristics. For this reason, they are not given formal recognition in this treatment.

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

Bromus grows in temperate and cool regions. It is estimated to include 100-400 species, the number depending on how the species are circumscribed. Of the 52 species in the Flora region, 28 are native and 24 are introduced. The native perennial species provide considerable forage for grazing animals, with some species being cultivated for this purpose. The introduced species, all but three of which are annuals, range from sporadic introductions to well-established members of the region's flora. Many are weedy and occupy disturbed sites. Some are used for hay; others have sharp, pointed florets and long, rough awns that can injure grazing animals.

This treatment is based on one submitted by Pavlick, who died before it could be reviewed and edited. It has been substantially revised by Anderton to meet the requirements for publication in this volume. The majority of Pavlick's taxonomic concepts are retained, despite the necessity for overlap in many key leads; time constraints prevented a thorough investigation of problematic taxa. The treatment recognizes taxa at both the subspecies and varietal rank; this simply reflects the decisions of the original author. We thank Hildemar Scholz of the Botanic Garden and Botanical Museum Berlin-Dahlem, Free University Berlin, for providing accurately identified specimens of the weedy European species for use in preparing the illustrations, and for his helpful suggestions for the keys and descriptions.

In the keys and descriptions, the distances from the bases of the subterminal lemma awns to the lemma apices are measured on the most distal florets in a spikelet.

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