CPC Plant Profile: Porter's Feathergrass
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Plant Profile

Porter's Feathergrass (Ptilagrostis porteri)

  • Global Rank: N/A
  • Legal Status: N/A
  • Family: Poaceae
  • State: CO
  • Nature Serve ID: 131237
  • Date Inducted in National Collection: 03/08/1989

Porter's false needlegrass, a small perennial bunchgrass that is a member of the Poaceae (Grass) Family can grow 20-35 cm tall. The fine and very narrow leaves are mostly basal. The one-flowered spikelets resemble the needlegrasses. The awn, a special part of the grass flower, is plumose along its entire length and twisted at the base. This plant is usually found in wetlands in fens and willow carrs. It flowers in early to late August. The fruits mature between mid August and early September. The plumose awns are persistent on the fruit, and the fruit could be dispersed by wind or animal (Harrington 1964; Johnston 2006; USFWS 2005; Von Bargen 1997). Ptilagrostis porteri was first discovered in 1892 by Charles C. Parry and by Elihu Hall and J.P. Harbour. Thomas C. Porter and J.M. Coulter named this plant Stipa mongholica in 1874. P.A. Rydberg determined that the plant did not suit the description of the Asiatic S. mongholica, but that it was a new species, and named it S.porteri for Tomas C. Porter, the first person to describe the species. This plant was first published by Weber in 1966, who moved it to the Asiatic genus Ptilagrostis. All species allied to S. mongholica have subsequently been moved to the genus Ptilagrostis in recent years (Barkworth 1983; Johnston 2006; Von Bargen 1997). Ptilagrostis porteri is listed as a sensitive species by both the U.S. Forest Service (Region 2) and the Bureau of Land Management for Colorado (U.S. Forest Service 2005 and USDI Bureau of Land Management 2004).

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Nature Serve Biotics
  • 05/02/2017

Ptilagrostis porteri has a restricted range in central Colorado. It occurs in a specific wetland habitat that is sensitive to disturbances, and only a few occurrences are expressly protected from peat mining and ditching, which threaten the element across its range.

Akiko Okawado
  • 01/01/2010

Threats include: - Hydrological alterations - Placer and peat mining - Heavy livestock grazing would have negative effects, while the effect of elk and deer grazing and browsing are unknown - Roads, trails, and recreational use such as off-road vehicl

Akiko Okawado
  • 01/01/2010

A total of 415,000 individuals are estimated. Although 29 sites are known for P. porteri, more than 90 percent of all known individuals exist in one large site. Three sites are represented by herbarium specimens (Johnston 2006).

Akiko Okawado
  • 01/01/2010

None known.

Akiko Okawado
  • 01/01/2010

There is no formal plan created for this plant.

Akiko Okawado
  • 01/01/2010

Research needs include understanding all aspects of P. porteri's ecology and biology, especially its life cycle, reproduction, dispersal, establishment, restoration, and demography.

Akiko Okawado
  • 01/01/2010

Seed collection and storage.


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Taxon Ptilagrostis porteri
Authority (Rydb.) W.A. Weber
Family Poaceae
CPC Number 3673
ITIS 519752
Common Names Porter's Feathergrass | Porter's false needlegrass
Associated Scientific Names Ptilagrostis porteri | Ptilagrostis mongholica | Stipa porteri | Ptilagrostis mongholica ssp. porteri
Distribution Endemic to El Paso, Lake, Summit and possibly Park Counties in central Colorado (Johnston 2006).
State Rank
State State Rank
Colorado S2

Porter's false needlegrass has very specific hydration requirements. This plant can grow on the tops and sides of elevated hummocks in peat fens. The hummocks are elevated above the water table, providing a slightly drier soil surface than the areas between hummocks. Elev. 9,200-12,000 ft. (Johnston 2006; Spackman 1997; USFWS 2005).This species is most commonly associated with Dasiphora floribunda, Betula glandulosa, Salix brachycarpa, Salix cadida, Salix planifolia, Thalictrum alpinum, Carex aquatilis, Deschampsia cespitosa, and Kobresia myosuroides (Johnston 2006).

Ecological Relationships

The plant is seemingly not palatable to herbivores. There have been a few reports of P. porteri plants lightly clipped by herbivores; however, P. porteri is more often left alone even when herbivores have obviously been present and neighboring plants have been grazed (Madsen 2004).

Common Name Name in Text Association Type Source InteractionID
Lead Institution State Reintroduction Type Year of First Outplanting

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