CPC Plant Profile: Porter's Reedgrass
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Plant Profile

Porter's Reedgrass (Calamagrostis porteri ssp. insperata)

This rare, cool season grass can grow up to 1 meter tall. Even when individuals in this species flower, like this one is, they rarely set viable seed. Photo Credit:
Description
  • Global Rank: N/A
  • Legal Status: N/A
  • Family: Poaceae
  • State: AR, IL, IN, KY, MO, OH
  • Nature Serve ID: 136063
  • Date Inducted in National Collection: 03/05/1993

Calamagrostis insperata is a rare, cool season grass. This tufted perennial can stand up to 1 meter in height and is very attractive. Plants are very sensitive to habitat conditions and rarely flower in the wild. Even when they do flower, they rarely set viable seed, and this likely contributes to the rarity of the species.

Participating Institutions
Updates
  • 08/31/2020
  • Reproductive Research

From a study involving 2000+ florets, a single viable caryopsis (seed) was observed. Thus, sexual reproduction is possible in this species, however, it is highly unlikely to occur in the wild (Havens and Holland 1998). A study of microhabitat relations found that C. insperata is affected by a complex suite of environmental factors, including: photosynthetic photo-flux density, vapor-pressure deficits, and soil temperature (Bittner and Gibson 1998).

Nature Serve Biotics
  • 05/02/2017

Calamagrostis porteri ssp. insperata is restricted to the central United States, including southern Ohio, Illinois, and Indiana, the Knobs region of Kentucky, and the Ozark Plateau region of Missouri and (historically) Arkansas. Approximately 80-100 occurrences are believed extant, mostly in Missouri. Most populations are small, especially in terms of reproductive individuals; plants very rarely flower, and few flowers produce viable seed. Full sun habitat, such as that created by fire, is believed to promote sexual reproduction. Threats include canopy closure from natural succession or fire suppression, clearcutting and resultant brush growth, grazing, soil compaction, recreational use of habitat, and loss of habitat to alternative land use (primarily agriculture). Many sites are on public lands, but needed prescribed burning and/or thinning management is not currently occurring at most.

Kimberlie McCue, Ph.D.
  • 01/01/2010

Threats include encroachment of woody vegetation (closure of canopy due to fire suppression), small population size and lack of seed production.

Kimberlie McCue, Ph.D.
  • 01/01/2010

Approximately 80 populations in five states.

Kimberlie McCue, Ph.D.
  • 01/01/2010

From a study involving 2000+ florets, a single viable caryopsis (seed) was observed. Thus, sexual reproduction is possible in this species, however, it is highly unlikely to occur in the wild (Havens and Holland 1998). A study of microhabitat relations found that C. insperata is affected by a complex suite of environmental factors, including: photosynthetic photo-flux density, vapor-pressure deficits, and soil temperature (Bittner and Gibson 1998).

Kimberlie McCue, Ph.D.
  • 01/01/2010

There is no formal management plan.

Kimberlie McCue, Ph.D.
  • 01/01/2010

Existing populations need to be protected and managed. Studies are needed to determine populations response to the creation of canopy gaps.

Kimberlie McCue, Ph.D.
  • 01/01/2010

Maintain genets from multiple populations.

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Photos
Nomenclature
Taxon Calamagrostis porteri ssp. insperata
Authority (Swallen) C.W. Greene
Family Poaceae
CPC Number 659
ITIS 523715
USDA CAPOI
Common Names Ofer Hollow reed grass | Porter's reedgrass | reed bent grass
Associated Scientific Names Calamagrostis porteri ssp. insperata | Calamagrostis insperata
Distribution Populations of C. insperata are scattered within five Midwestern states: Illinois, Indiana, Kentucky, Missouri, and Ohio (Summers 1993). The species may have once occurred in Arkansas, but is now bel
State Rank
State State Rank
Arkansas SH
Illinois S1
Indiana S1
Kentucky S1S2
Missouri S3
Ohio S2
Habitat

C. insperata often grows in forest openings and along edges of upland woods (Bittner and Gibson 1988). However, its habitat can vary greatly. Many plants can be found on cool, north-facing sandstone bluff edges.Associated canopy species include: Quercus spp., Acer rubrum, Cornus florida. Ground vegetation species include: Monarda bradburiana, Hedyotis longifolia, Polystichum acrostichoides (Bittner and Gibson 1988).

Ecological Relationships

None known.

Pollinators
Common Name Name in Text Association Type Source InteractionID

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