Torreyochloa pallida (Torr.) Church
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Puccinellia pallida, Glyceria pallida, Glyceria fernaldii, Puccinellia fernaldii
Basis for Listing
There are two recognized varieties of Torreyochloa pallida occurring in Minnesota: T. pallida var. fernaldii (Hitchc.) Dore and T. pallida (Torr.) Church var. pallida. Torreyochloa pallida var. fernaldii is primarily a northern species ranging across portions of Canada and south through the upper Great Lakes states to greater New England. Torreyochloa pallida (Torr.) Church var. pallida ranges primarily in the northeastern U.S. and Canada, occurring westerly to Manitoba and Minnesota and south to Missouri and Georgia.
Torreyochloa pallida is a perennial grass with decumbent stems that typically root at the lower nodes. The leaf sheaths are open to the base. The inflorescence is a terminal panicle; the lower glume is 1(3) nerved and the upper glume is (1)3(5) nerved. The lemmas are membranous and strongly (5)7-9 veined. Specimens of T. pallida that fit var. fernaldii have cauline leaves that are 1.5-3 mm (0.06-0.12 in.) wide with anthers of the lowest floret of each spikelet that are 0.3-0.6 mm (0.012-0.024 in.) long. Specimens of T. pallida that fit var. pallida have cauline leaves 2.8-9(11.4) mm (0.11-0.35 in.) wide with anthers of the lowest floret of each spikelet that are 0.7-1.5 mm (0.028-0.06 in.) long (Davis 2007).
Torreyochloa pallida occurs in a wide variety of wetland habitats including the shores and shallows (0.3-0.9 m; 1-3 ft.) of streams, lakes, vernal ponds, and beaver ponds. Water is often slower moving and substrates are typically mucky. The species also occurs in Fraxinus nigra (black ash) swamps and bogs (poor fen). Associated plant species include Glyceria canadensis var. canadensis (rattlesnake grass), G. grandis var. grandis (tall manna grass), G. striata (fowl manna grass), Sium suave (water parsnip), and Calla palustris (wild calla).
Biology / Life History
Torreyochloa pallida is a perennial grass and an obligate wetland species in Minnesota (Milburn et al. 2007). It occurs as both scattered, small patches of plants and as large, robust colonies of 1,000s of culms. The species propagates by seed and vegetatively by rhizomes. The rooting nature of the culms may also allow broken and dislodged portions of the plants to further establish themselves. The decumbent growth form and rooting culms are distinctive when observed growing as loosely tangled mats along the sunny, mucky shores and shallows of slow moving streams.
Conservation / Management
Although detection of T. pallida and documentation of its distribution in Minnesota has improved, we know little more regarding the species' biology and how populations are responding to management activities and a changing environment. Potential threats to T. pallida include outright habitat destruction and physical, chemical, or hydrological alterations of habitat conditions. Ample opportunity exists across land ownerships to learn more about the dynamics of this wetland species.
Conservation Efforts in Minnesota
While most T. pallida populations occur on state and federal land, few occur in areas that are formally protected and designated, such as Scientific and Natural Area, State Parks, or the Boundary Waters Canoe Area Wilderness.
References and Additional Information
Davis, J. I. 2007. Torreyochloa. Pages 607-609 in Flora of North America Editorial Committee, editors. Flora of North America North of Mexico. Volume 24. Oxford University Press, New York, New York.
Milburn, S. A., M. Bourdaghs, and J. J. Husveth. 2007. Floristic quality assessment for Minnesota wetlands. Minnesota Pollution Control Agency, St. Paul, Minnesota. 197 pp.
Voss, E. G. 1972. Michigan Flora: Part I Gymnosperms and Monocots. Cranbrook Institute of Science Book 55, Bloomfield Hills, Michigan. 488 pp.