Section Acrocystis
Species in Section Acrocystis (formerly Sect. Montanae), are among the earliest-flowering sedges in the Mid-Atlantic, sometimes blooming as early as March. The earliest species are usually those with ‘subradical spikes’ – pistillate spikes which arise from basal nodes and are often obscured among tufts of leaves. Note that Carex reznicekii and Carex nigromarginata can also have pistillate spikes on short peduncles, but these are always produced in association with staminate spikes.
Interestingly, the perigynia of these sedges are ant-dispersed. As they mature, the perigynia become fleshy and whitish, attracting ants which collect the fruits and transport them into their network of tunnels. Occasionally, swollen, black perigynia may also be found – these are the result of fungal infections.
White-tinged Sedge (Carex albicans var. albicans)
Habitat: Dry to mesic woodlands and forests.
Characteristics: Plants cespitose; subradical spikes NOT present; culms erect-to-ascending and conspicuous, equaling-to-exceeding the length of the leaves; perigynia are trigonous in cross-section; pistillate scales with green midrib, hyaline margins, and usually with a red tinge; staminate scales in the middle of the spike with midribs that do not extend to the tip.
Global Rank/State Rank: G5/S5
Comments: This taxon is most similar to two others:
- Carex albicans var. australis which is more strongly rhizomatous, forming clonal patches.
- Carex emmonsii which has culms that are shorter than and often hidden by the leaves. The staminate scales also have midribs that extend to the tip and may even appear as aristate projections.
Southern White-tinged Sedge (Carex albicans var. australis)
Habitat:
Characteristics:
Global Rank/State Rank: N/A
Fibrous-rooted Sedge (Carex communis)
Habitat: Dry to mesic forests
Characteristics: Densely to loosely cespitose; bases purplish; leaves 1.8-4.7 wide; ligule longer than the width of the leaf; culms scabrous distally; body of perigynia round to obtusely trigonous in cross-section
Global Rank/State Rank: G5/S5
Emmons's Sedge (Carex emmonsii)
Habitat:
Characteristics:
Global Rank/State Rank: N/A
Black-edged Sedge (Carex nigromarginata)
Habitat: Dry to dry-mesic forests; often encountered in mixed-oak and oak-hickory forests.
Characteristics: Plants cespitose; leaves surpassing the culms; pistillate spikes clustered with staminate spike at the top of culms
Global Rank/State Rank: G5/S5
Comments: A handsome sedge with pistillate scales that are dark-purple to black along the margin.
Pennsylvania Sedge (Carex pensylvanica)
Habitat: Dry to dry-mesic forests, open woodlands, and in dry clearings.
Characteristics: Loosely cespitose, often forming aggregations of loose clumps that may become dense stands under ideal conditions; rhizomes elongate, reddish brown to dark brown, and with a fibrous exterior; leaves 1-3 mm wide; perigynia pubescent, round to obtusely trigonous in cross-section.
Global Rank/State Rank: G5/S5
Comments: Despite being widely distributed across Virginia, this species is uncommon in Fairfax County. I have only come across it once since 2018.
Reznicek's Sedge (Carex reznicekii)
Habitat: slopes of oak-hickory forests.
Characteristics: Densely cespitose; Leaves 1-2.5 mm wide, surpassing the culms; pistillate scales with greenish to brownish midvein, hyaline margins, and usually with a submarginal stripe; perigynia pubescent.
Global Rank/State Rank: N/A
Comments: A recently-described species that shares similar characteristics with other taxa in this section.
Parachute Sedge (Carex rugosperma)
Habitat:
Characteristics:
Global Rank/State Rank: N/A
Shaved Sedge (Carex tonsa)
Habitat: Dry woodlands and clearings
Characteristics: Plants cespitose; Leaves to 4.3 mm wide, exceeding culms; Perigynia essentially hairless (a few hairs may occur on the angles of the beak), trigonous in cross-section.
Global Rank/State Rank: G5/S5
Comments: In comparison to Carex rugosperma and C. umbellata, this species has short, broad leaves and the essentially hairless perigynia.
Parasol Sedge (Carex umbellata)
Habitat:
Characteristics:
Global Rank/State Rank: G5/S5