This species was first collected by Elmira botanist T. F. Lucy on Sullivan's Hill in Chemung County from 1882 to 1897. It was not collected again until 1944 when Stanley Smith from the New York State Museum collected it behind the Elmira Reservoir on Hoffman Hill.
There is one existing population of thousands of plants that has been known since 1895. There are seven historical populations known from the first half of the 1900s.
The short-term trend is stable with no large fluctuations in the number of populations.
This plant has always been very rare in New York with a very limited distribution. Most of the historically known populations have not been surveyed in detail, so the long-term trends are unclear.
Piles of raked leaves were dumped on part of the single known population but that situation was corrected. There are no other known threats at present.
The known population should be periodically monitored for any changes in landscape management of the area.
There are no known research needs at this time.
The only known extant site for this grass in New York is a dry oak-hickory ridgetop forest with shaly soils. Historical collections also note dry or shaly woods and edges (New York Natural Heritage Program 2013). Roadsides and open woods; mostly at elevations of 1000-2000 feet (Rhoads and Block 2000). Dry rocky ridge-top forests (Gleason and Cronquist, 1991). Dry upland woods (Fernald, 1970).
In New York this species is known only from the southern tier, from Tioga County west to Steuben County.
Porter's Reedgrass reaches its northeastern limit in New York state. Subspecies porteri has a relatively narrow distribution through the Appalachians as far south as Kentucky and North Carolina.
Calamagrostis porteri ssp. porteri is a grass that grows in loose clumps with stems to 1 meter tall. The leaves are 8 to 40 cm long and 2 to 8 mm wide (typically 3 to 6 mm), light green and glaucous on their upper surfaces, and darker green below. The summit of the leaf sheath (collar) and often the base of the leaf blade are bearded. The stem typically has 4 leaves. As in all grasses, the small, inconspicuous flowers occur in scaly structures called spikelets. In the genus Calamagrostis each spikelet contains only one flower. The flowers are borne in narrow, elongated panicles with individual spikelets from 3.5 to 5 mm long. The lower spikelet bract (lemma) is 3 to 5 mm long with an awn 3 to 4.5 mm long and bent or twisted below, protruding (exserted) from the bracts subtending the spikelet (glumes). Hairs are present on the hardened base of the floret (callus) in 2 separated tufts, 1.5 to 2 mm long (40 to 60% the length of the lemma). (Marr et al 2007)
Calamagrostis porteri ssp. porteri is a grass that grows in loose clumps with stems to 1 meter tall. The leaves are 8 to 40 cm long and 2 to 8 mm wide (typically 3 to 6 mm) with light green, glaucous upper (adaxial) leaf surfaces, and darker green lower (abaxial) surfaces. The summit of the leaf sheath (collar) and often the base of the leaf blade are bearded. The stem typically has 4 leaves. Flowers are borne in narrow, elongated panicles with individual spikelets from 3.5 to 5 mm long. The lower spikelet bract (lemma) is 3 to 5 mm long with an awn 3 to 4.5 mm long and bent or twisted below, protruding laterally (exserted) from the bracts subtending the spikelet (glumes). Hairs are present on the hardend base of the floret (callus) in 2 separated tufts, 1.5 to 2 mm long (40 to 60% the length of the lemma). (Marr et al 2007)
Plant stems including mature fruit with intact glumes, lemmas, and leaves are needed for proper identification.
There are eleven other taxa of Calamagrostis in New York, but most of them are plants of wetland or lowland habitats. C. epigejos has callus hairs 1.5 to 2 times as long as the lemma and is known primarily from roadsides and waste places. C. perplexa is a globally rare species of upland forests, and is closely related to C. porteri. C. perplexa differs by having a lax or nodding panicle, longer callus hairs, and sometimes branching stems. Calamagrostis porteri ssp. porteri is our only subspecies.
Mature fruits typically form in August, persisting until the first frost.
The time of year you would expect to find Porter's Reed Grass fruiting in New York.
Porter's Reed Grass
Calamagrostis porteri ssp. porteri None
All of our Calamagrostis porteri are subspecies porteri.
Marr, K.L, R. J. Hebda, and C. W. Greene. 2007. Calamagrostis Adans. Pages 706-731 in Flora of North America Editorial Committee (Editors), Flora of North America, north of Mexico, Volume 24, Magnoliophyta: Commelinidae (in part): Poaceae, part 1. Oxford University Press, New York, NY, USA. 911pp + xxviii.
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. 1986. A checklist of New York State plants. Bulletin No. 458. New York State Museum. 272 pp.
New York Natural Heritage Program. 2023. New York Natural Heritage Program Databases. Albany, NY.
Rhoads, A.F. and T.A. Block. 2000. The Plants of Pennsylvania: An Illustrated Manual. University of Pennsylvania Press: Philadelphia, Pennsylvania. 1061 pp.
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
This guide was authored by: Stephen M. Young, Elizabeth Spencer, Richard M. Ring.
Information for this guide was last updated on: October 25, 2022
Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Calamagrostis porteri ssp. porteri. Available from: https://guides.nynhp.org/porters-reed-grass/. Accessed January 30, 2023.