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Purple False Oats (Trisetum melicoides)
Purple False Oats (Trisetum melicoides), a State Endangered plant, is found in mixed forests near Lake Michigan, as well as in ridge and swale systems and on shoreline dolomite and seeping bluffs. Blooming occurs from June. The optimal identification period for this species is mid-July to late August.
Synonyms: Aira melicoides; Graphephorum melicoideum; G. melicoides var majus; T. melicoides var. majus
- Distinguishing characteristics: Can be distinguished from the only other Trisetum species in Wisconsin by height (greater than 30 cm) and the absence of awns on spikelets.
- Flower characteristics: Panicle somewhat open, nodding, 10 to 20 cm long; branches slender, ascending, lax or drooping, as much as 7 cm long, rather closely flowered above the middle; spikelets scaberulous, 6 to 7 mm long.
- Fruit characteristics: Glumes 4 to 6 mm long, the second longer and broader; lemmas acute, 5 to 6 mm long, rarely with a minute awn just below the tip; the rachilla and callus hairs 1 to 2 mm long.
- Leaf characteristics: Leaf blades 2 to 8 mm wide, scabrous, sometimes pubescent on the upper surface; Sheaths pubescent or scabrous.
- Blooming phenology: June
- Fruiting phenology:
- Optimum time to identify: mid-July to late August
- Growth form: Graminoid
- Vegetative reproduction:
- Life cycle: Perennial
- Comments: Associated Species: Acer saccharum, Fagus grandifolia, Tilia americana, Thuja occidentalis, Abies balsamea, Carex eburnea, C. concinna, Trientalis borealis, Cornus canadensis, Parnassia glauca, Halenia deflexa, Polygala paucifolia.
Status and Natural Heritage Inventory documented occurrences in Wisconsin
The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Purple False Oats (Trisetum melicoides). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.
|Federal Status in Wisconsin||none|
|Tracked by NHI||Y|
Habitats and landscapes
The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.
General habitat information
- Habitat description: Found in mixed forests near Lake Michigan, as well as in ridge and swale systems and on shoreline dolomite and seeping bluffs.
- Soils: Gravelly or rocky soils
This table lists the natural communities that are associated with Purple False Oats. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).
|Great Lakes Ridge and Swale||2|
|Clay Seepage Bluff||1|
|Great Lakes Alkaline Rockshore||2|
This table lists the ecological landscape association scores for Purple False Oats. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.
The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.
Purple False Oats (Trisetum melicoides) has very few known occurrences in the state and is of the highest priority for conservation; we encourage you to consult with your District Ecologist or NHI Botanist for specific recommendations for your site.
These are specific actions designed to avoid "take" (mortality) of this species.
- Avoid disturbance to streambanks and calcareous rock ledges within forests where this species has been reported
- Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
- Avoid broadcast spraying of herbicides; use care with spot spraying.
Management guidelines are additional considerations that may help maintain or enhance habitat for this species
- Buffer management around unique microhabitats such as ephemeral ponds, seeps, etc.
- Minimize disturbance to hydrology, including soil disturbance from rutting.
- Follow BMPs, especially around streams and use care near ravines, steep slopes, cliffs, rock outcrops, etc.
Links to additional Purple False Oats information
Other links related to vascular plants (all exit the DNR website)
- Wisconsin Vascular Plants
- Freckmann Herbarium
- Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
- USDA - NRCS Plants Database
- USGS Midwestern Wetland Flora - field office guide to plant species
- Cofrin Center for Biodiversity Herbarium
- Intermountain Herbarium Grasses of North America
- Orchids of Wisconsin
Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin.