COMMON NAME

Silver hairgrass

FULL SCIENTIFIC NAME

Aira caryophyllea L.

FAMILY NAME COMMON

Grass family

FAMILY SCIENTIFIC NAME

Aira caryophyllea

IMAGES

Habit	Incursion	Inflorescence
Plant

NOMENCLATURE/SYNONYMS

Synonyms: Aspris caryophyllea (L.) Nash

DESCRIPTION

Botanical Glossary

Aira caryophyllea is an herbaceous annual that grows 5-30 cm (2-12 in.) in height. The culms of this plant are very slender. The sheaths and thread-like blades are rough to the touch. Most of the sheaths are basally located. The ligule is 3 mm (0.125 in.) long. The blades are involute and bristle-like, measuring 1-4 mm (0.04-0.2 in.) in length. The panicle is open and spreading, with ascending branches and silvery spikelets. The glumes are 2.3-3 mm (0.1 in.) long and the lemmas measure 1.8-2.3 mm (0.07-0.1 in.) long. Both the glumes and the lemmas have awns that measure 2.4-3.3 mm (0.1-0.13 in.) long. The flowers appear from May to early July. The plants die and disappear by mid July. Page References Fernald 148, Gleason & Cronquist 764, Holmgren 713, Magee & Ahles 181. See reference section below for full citations.

SIMILAR SPECIES

Aira praecox (L.) Nash (Early hairgrass)
Poa annua L. (Annual bluegrass) Aira praecox can be distinguished from Aira caryophyllea by its tighter panicle and longer lemmas. Poa annua is a coarser plant that roots at its nodes, with heavier flowers and folded, flat leaves.

REPRODUCTIVE/DISPERSAL MECHANISMS

Aira caryophyllea reproduces by wind-dispersed seeds. It is possible that its seeds are also dispersed by getting caught up in fur, clothing and automobiles.

DISTRIBUTION

Aira caryophyllea is native to the northern parts of Africa and most of Europe to the western part of Asia (from Ireland to Italy and Portugal to Russia and Turkey). In the United States this plant has been reported from New Hampshire to Georgia and west to Missouri, Oklahoma and Texas. It is also found along the west coast from Washington to California and east to Idaho and Wyoming. Aira caryophyllea has been reported from all of the states of New England except Maine and Rhode Island.

HISTORY OF INTRODUCTION IN NEW ENGLAND

Records from New York and Philadelphia from the 1870's indicate that Aira caryophyllea was probably first introduced to North America as a ballast soil contaminant. The earliest records of Aira caryophyllea in New England come from Nantucket, Massachusetts in the 1880's. By 1908, Aira caryophyllea was "widely scattered over the island and locally very common" (Bulletin of the Torrey Botanical Club. Vol. 35: 119). Aira caryophyllea wasn't reported in any other New England locations until 1913 when it was first noted in a sandy field in Wellfleet on Cape Cod (Rhodora. Vol. 16: 78). Fernald (1950) noted that Aira caryophyllea was found in "sandy fields and waste places" in southeast Massachusetts.

HABITATS IN NEW ENGLAND

Aira caryophyllea grows well in dry, sandy soils. It is most common in coastal regions, but it can be found further inland, particularly along roadways (interstate highways). It tends to grow in patches, occasionally spreading to cover larger areas.

THREATS

Aira caryophyllea does not appear to spread rapidly, and therefore it may not be a serious threat to natural environments in New England. However, it has been demonstrating an ability to grow in large patches and should be monitored for other invasive tendencies.

MANAGEMENT LINKS

DOCUMENTATION NEEDS

Documentation required: Herbarium specimen or mounted snippet of the plant.
Best time for documentation: Early summer.

ADDITIONAL INFORMATION

Integrated Taxonomic Information System
Taxonomic information about the species

The PLANTS Database
General information and map

GRIN database
Information about native range

British Columbia Ministry of Forests
Description and line drawings

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.

Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual.  New York Botanical Garden, Bronx, New York.

Magee, D.W and H.E. Ahles. 1999.  Flora of the Northeast. University of Massachusetts Press, Amherst.

USDA, NRCS.  2001.  The PLANTS Database, Version 3.1. (http://plants.usda.gov).  National Plant Data Center, Baton Rouge, LA 70874-4490 USA.