FULL SCIENTIFIC NAME
Bromus tectorum L.
FAMILY NAME COMMON
FAMILY SCIENTIFIC NAME
Synonyms: Anisantha tectorum (L.) Nevski
Bromus tectorum is an erect-stemmed annual grass that grows 20-70 cm (8-25 in.) in height. Its leaf sheaths and blades are covered with soft short hairs. The leaves are 2-4 mm (0.08-0.16 in.) wide and up to 20 dm (8 in.) long. Its ligules are 1-2.5 mm (0.04-0.1 in.) long. The panicles measure 5-20 cm (2-7.75 in.) long, have numerous branches, retain an open quality and are generally nodding. The panicles bear from 3 to 8 drooping spikelets, each spikelet is 2-3.5 cm (0.8-1.4 in.) long. The glumes are awl-shaped. The lemmas are narrowly lanceolate, 1-1.5 mm (0.04-0.06 in.) wide, toothed, and sometimes hairy. They have slender, straight awns that are 10-17 mm (0.4-0.67 in.) long. Bromus tectorum flowers from May to June. Its foliage and inflorescences are a shiny light green up to the flowering period, but then turn a wine-red color after flowering, and eventually turn brown as they senesce. Most of the plants usually die and fall over by July. The seeds of Bromus tectorum can germinate in the fall or in the spring; fall germination is generally more common. B. tectorum has a fibrous root system is finely divided. When a seed germinates in the fall, the developing root system is able to expand over the winter, giving the plant an increased ability to exploit available water and nutrients in the spring. Page References Fernald 103, Gleason & Cronquist 773, Holmgren 723, Magee & Ahles 163. See reference section below for full citations.
Bromus tectorum reproduces by seeds that are dispersed by gravity, wind and other mechanical means. The awns on each of its florets are barbed and capable of piercing and adhering to fur and clothing. This promotes the seed's dispersal through "hitching rides" on animals, people and even vehicles.
Bromus tectorum is a native of Mediterranean Europe. It gets the name "tectorum", which means roof, from its historical penchant for growing on thatched roofs. It is currently present in all fifty of the United States, all of the Canadian provinces and parts of Mexico. It is much more abundant in the western U.S. and Canada, notably in regions where the annual rainfall is between 15 and 55 cm (5.9-21.7 in.). It is most problematic on heavily grazed rangeland and regions where winter wheat is grown. Bromus tectorum is on the noxious weed lists of at least 35 states. In New England, it is found mostly along roadsides and in disturbed areas.
HISTORY OF INTRODUCTION IN NEW ENGLAND
Bromus tectorum was first introduced to North America sometime before 1860; in the years that followed it was probably introduced many times, at a wide range of different sites. There is evidence that Bromus tectorum arrived as a seed lot contaminant, and also in ballast soil. Its spread around the country may have been aided by trains, because it was often found in straw that was used in the rail system as packing material. The earliest North American records come from wheat field regions in Washington, Utah, Colorado, Montana and British Columbia. The common name "cheatgrass" comes from western farmers who thought they had been given impure seed when Bromus tectorum started spreading into their wheat fields. It spread quickly during the late 19th and early 20th century. By 1920 to 1930, Bromus tectorum had arguably become the worst weedy range grass in the western United States. It is currently the dominant species on more than 100 million acres of land in the intermountain West. The first records of Bromus tectorum are from New York and Pennsylvania in 1861. There are many other records of Bromus tectorum in the Northeast from the 1870's, mostly in sandy waste sites not far from the coast. Robinson and Fernald (1908) described it as being found in "waste places from Maine to Illinois and southward". By 1950, Fernald described it as being found at "roadsides and waste places, often too abundant". It is presently common in all of the states of New England, though it does not pose the sorts of problems in the Northeast that it does out West.
HABITATS IN NEW ENGLANDAbandoned Field,Agricultural Field,Edge,Open Disturbed Area,Pasture,Railroad Right-of-Way,Utility Right-of-Way,Vacant Lot,Yard or Garden
In New England Bromus tectorum is mostly found in disturbed sites, waste areas and along roadsides. It grows well in areas with dry, sandy soil.
Bromus tectorum has the ability to draw down soil moisture and nutrients to very low levels, making it difficult for other species to compete. An increased cycle of fires favors annual species at the expense of many perennials. Due to its tendency to mature early and then dry out, B. tectorum gains a competitive advantage through the promotion of fire. Though very important to Bromus tectorum's success out West, this fire dynamic has not helped it in New England. Bromus tectorum is a serious agricultural weed in the western U.S., but in New England it is starting to have an impact in nursery and orchard settings.
Documentation required: Herbarium specimen or mounted snippet of a branch with flowers or fruits.
Best time for documentation: Spring, summer, fall.
Integrated Taxonomic Information System
Taxonomic information about the species
The PLANTS Database
General information and map
The Nature Conservancy
Extensive descriptive and control information
USDA Forest Service Fire Effects Information System (FEIS)
Extensive ecological information
Montana State weed science
Has description, pictures and control information
Fernald, M.L. 1950. Gray's Manual of Botany 8th edition. American Book Company, New York. Gleason, H. A. 1952. The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada. Macmillan Publishing Co., Inc. New York Gleason, H.A. and A.C. Cronquist. 1991. Manual of Vascular Plants of the Northeastern United States and Adjacent Canada. 2nd ed. New York Botanical Garden, Bronx, New York. 773. Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual. New York Botanical Garden, Bronx, New York. Hulbert, L. 1955. Ecological studies of Bromus tectorum and other annual bromegrasses. Ecol. Monogr. 25:181-213. Mack, R. N. 1981. Invasion of Bromus tectorum L. into western North America: an ecological chronicle. Agro-Ecosyst. 7:145-165. Magee, D.W and H.E. Ahles. 1999. Flora of the Northeast. University of Massachusetts Press, Amherst. Morrow, L. A. and P W. Stahlman. 1984. The history and distribution of downy brome (Bromus tectorum) in North America. Weed Sci. 32:2-6. Robinson, B.J. 1908. Gray's New Manual of Botany, 7th ed. American Book Co., New York, NY. USDA, NRCS. 2001. The PLANTS Database, Version 3.1. (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.