This grass likes damp sands, often in parks or roadsides, where the plants are often mowed before they can reveal their attractive seed heads.
There are five existing populations but two of them have less than 50 plants. Population sizes change substantially year-to-year because of their dynamic habitat and mowing regimes. This grass has always been rare in New York with only six historical occurrences.
The large populations seem to be fairly stable. Two small populations have not been revisited.
The number of populations in New York has always been very small even though there seems to be much habitat. This stable trend will probably continue into the future.
Since plants occur on the borders of roads and fields, the main threats to populations are improper mowing regimes, which may reduce plants if mowed too often or increase competition if not mowed often enough.
This species needs disturbance to reduce competition from woody plants or more aggressive herbaceous plants but too much direct disturbance to the plants will reduce or eliminate the population. Its habitat could be disturbed in the non-growing season to open it up for seed germination and colonization but direct disturbance should be prevented during the growing season.
We need to know why this plant is so restricted in distribution even though it occurs in common disturbed habitats such as roadsides.
Damp meadows, fields, mowed roadsides, mowed grounds, and lawns. Associated species include Trifolium pratense, Plantago major, Plantago lanceolata, Allium vineale, Digitaria, Polygonum aviculare, Setaria and Taraxacum, Daucus carota (New York Natural Heritage Program 2010). Edges of forests and in disturbed areas (FNA 2003). Damp sandy fields, savannas, thickets and shores (Fernald 1970).
This grass is currently only known from Suffolk County but there are historical records west to Staten Island, the Bronx, and Westchester County.
It is most common in the South-Central and Eastern US with scattered populations north to the Midwest and Coastal New York and New England.
Field Beadgrass is a perennial grass, growing from short rhizomes. The stems are erect and from 40 to 120 centimeters tall, often with several growing together from the base. The leaves have keeled, sometimes hairy sheaths and blades about 5 to 25 cm long and 2 to 10 mm wide. The fruit are borne in from 1 to 6 branches, each arranged as a raceme of singly borne spikelets packed tightly together and close to the stem. The spikelets themselves are elliptical or obovate to round (bead-like), glabrous, about 2.3 to 3.3 millimeters long and nearly as wide, and have 3-veined upper glumes and 5-veined, sterile lemmas (FNA 2003).
Field beadgrass is best identified when in fruit.
The only other species of genus Paspalum in New York is P. setaceum. There are four varieties of P. setaceum known from New York. All of them differ from P. laeve by having paired spikelets and sterile lemmas with two or three veins (P. laeve has solitary spikelets and five-veined sterile lemmas.)
This grass is best surveyed for from mid-summer into fall.
The time of year you would expect to find Field Beadgrass fruiting in New York.
Paspalum laeve Michx.
Flora of North America Editorial Committee. 2003. Flora of North America, North of Mexico. Volume 25. Magnoliophyta: Commelinidae (in part): Poaceae, part 2. Oxford University Press, New York. 783 pp.
Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.
Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.
Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.
Mitchell, Richard S. and Gordon C. Tucker. 1997. Revised Checklist of New York State Plants. Contributions to a Flora of New York State. Checklist IV. Bulletin No. 490. New York State Museum. Albany, NY. 400 pp.
New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.
New York Natural Heritage Program. 2019. New York Natural Heritage Program Databases. Albany, NY.
Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York
Information for this guide was last updated on: April 11, 2011
Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Paspalum laeve. Available from: https://guides.nynhp.org/field-beadgrass/. Accessed September 24, 2019.