| Author | A. Gray | |
| Distribution | The southern 2/3 of the Mountains; disjunct to Surry County in the upper Piedmont. As it occurs in nearly all of the VA mountain counties, it should eventually be found in the northern mountain counties in NC, as suitable habitat seems to be widespread.
Montane, from NY to AL. | |
| Abundance | Rare to uncommon in the southern and central mountains, but very rare in the northwestern Piedmont. This is a Significantly Rare species. | |
| Habitat | Dry to mesic, usually rocky, mixed hardwood-deciduous forests, cliff bases. Seems to prefer mafic/calcareous rocks, explaining its scarcity, though some records do not seem to be from such rocks. | |
| Phenology | Flowering and fruiting July-September. According to Weakley (2018): "This species is typically sterile unless disturbed by fire or mechanically; it is therefore probably more common than collections indicate." | |
| Identification | Cain's Reedgrass (C. cainii) and Porter's Reedgrass are best told from Bluejoint Reedgrass (C. canadensis) by having awns surpassing the lemmas (vs. shorter than the lemmas in C. canadensis). From Cain's Reedgrass, Porter's is readily told by its wider leaves (3-8 mm wide vs. 2-3 mm wide in the latter species) and a denser inflorescence. | |
| Taxonomic Comments | A second variety (insperata) occurs from OH and TN to MO and AR.
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| Other Common Name(s) | None | |
| State Rank | S2 | |
| Global Rank | G4 | |
| State Status | SR-P | |
| US Status | | |
| USACE-agcp | | |
| USACE-emp | | |
