Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
| 1 Perigynia with a distinct beak, 1.0-2.2 mm long. |
| ..2 Basal leaves with well-developed blades; basal sheaths brown; perigynia glabrous; [of moist, usually calcareous habitats of the Coastal Plain] |
| ..2 Basal leaves reduced to bladeless sheaths; basal sheaths strongly purple; [of dry, acidic habitats of the Mountains] |
| 1 Perigynia beakless, or with an indistinct beak < 0.5 mm long. |
| ....3 Perigynia strongly ascending; leaves coriaceous, involute, glaucous; [s. NJ northwards] |
| ....3 Perigynia ascending or spreading; leaves herbaceous, flat or folded, green or slightly glaucous; [collectively widespread]. |
| ......4 Basal sheaths with well-developed blades; basal sheaths brown to strongly purple. |
| ........5 Pistillate spike 5-7 mm in diameter, with ca. 6 vertical rows of perigynia; perigynia 3.3-4.2 mm long, 2.0-2.5 mm wide; leaves 3-7 mm wide, blue green |
| ........5 Pistillate spike 3-4 mm in diameter, with ca. 2-3 vertical rows of perigynia; perigynia 2.5-3.5 mm long, 1.5-2.0 mm wide; leaves 2-4.5 mm wide, pale green |
| ......4 Basal sheaths bladeless, or with blades to 3 cm long; basal sheaths strongly purple. |
..........6 Culms to 10 dm tall, (2-) 3-5 mm in diameter near base; larger leaves ca. 5 mm wide; plants forming large clumps; [plants of shallow soils on sloping rock outcrops] |
| ..........6 Culms to 5 dm tall, ca. 1-2 mm in diameter near the base; larger leaves ca. 2-4 mm wide; plants forming small, spaced clumps, interconnected by long-creeping rhizomes; [plants of mountain slopes in more-or-less deep soils] |