1 Leaves 1-15 mm wide (to 30 mm wide in P. setosum), mostly > 3× as long as wide (except in P. nudum); calyx lobes not tipped with a tuft of long, jointed bristles (except P. clinopodioides). |
2 Longer calyx lobes 1.5-5 mm long, attenuate- aristate, stiff, whitened; [Coastal Plain pinelands, rarely in Mountain bogs with Coastal Plain affinities]. |
3 Principal stem leaves 5-15 mm wide |
3 Principal stem leaves 10-30 mm wide |
2 Longer calyx lobes 0.5-1.6 mm long, deltoid to narrowly triangular, not notably stiff (except in P. tenuifolium) or whitened; [widespread in our area, but mainly of the Piedmont and Mountains]. |
4 Leaves 10-15 mm wide (or more often even wider, to 25 mm wide, in P. clinopodioides); longer calyx lobes 0.7-1.6 mm long, tipped with a few long (1-3 mm) jointed bristles ( P. clinopodioides) or not tipped ( P. nudum). |
5 Leaves 1-2.5× as long as wide, coriaceous; stems and leaves glabrous; [Coastal Plain, se. SC southward and westward to FL and AL] |
5 Leaves 3-6× as long as wide, herbaceous; stems and leaves pubescent; [inland provinces and Coastal Plain, NC northward] |
6 Calyx zygomorphic, the lower 2 teeth about 1.5× as long as the upper 3; [mainly Coastal Plain, disjunct in mountains; SC and NC northwards] |
6 Calyx actinomorphic, the teeth similar in shape and size, all 0.5-1.0 mm in length; [primarily inland] |
4 Leaves 1-12 (-15) mm wide; longer calyx lobes 0.5-1.5 mm long, variously pubescent but not tipped with a tuft of long jointed bristles. |
7 Leaves glabrous on the lower and upper surface, with 2-3 pairs of lateral veins; stems glabrous on the faces and angles (rarely with a few small upwardly-curled hairs on the angles). |
8 Leaves 5-15 mm wide, 1-2.5× as long as wide; calyx lobes and inner bracts of the inflorescence herbaceous |
8 Leaves 1-4 (-5.5) mm wide, 8-15× as long as wide; calyx lobes and inner bracts of the inflorescence semi-spinose, their tips subulate, thickened, and stiff |
7 Leaves pubescent at least on the lower surface along the midrib and main veins; leaves with 4-5 pairs of lateral veins; stems glabrous or pubescent on the faces, pubescent on the angles. |
9 Stems pubescent on the angles only (or distinctly less pubescent on the faces); leaves 3-10 mm wide |
9 Stems pubescent on the faces and angles, the hairs distributed more-or-less evenly; leaves 8-12 (-15) mm wide. |
10 Longer calyx teeth 1.0-1.5 mm long, lanceolate and attenuate; bracts of the inflorescence and leaves glabrous or very sparsely pubescent on the upper surface |
10 Longer calyx teeth 0.5-1.0 mm long, narrowly deltoid; bracts of the inflorescence (and usually also the leaves) canescent on the upper surface |
1 Leaves broad, 15-40 mm wide, mostly 1.5-3× as long as wide; calyx lobes usually tipped with a tuft of long, jointed bristles (except P. albescens, P. curvipes, P. floridanum, P. muticum varieties, P. setosum). |
11 Bracts of the inflorescence glabrous (or very sparsely pubescent) on the upper surface, the margins long- ciliate; calyx lobes and upper part (at least) of the tube with long spreading hairs (independent of the apical tufts) |
11 Bracts of the inflorescence puberulent on the upper surface, the margins not ciliate; calyx lobes and tube variously glabrous or puberulent (independent of the apical tufts). |
12 Calyx lobes not tipped with a tuft of long, jointed bristles. |
13 Calyx lobes 1.5-3 mm long, attenuated into a subulate tip; [Coastal Plain] |
13 Calyx lobes 0.5-1.2 (-1.5) mm long, triangular to narrowly triangular, acute to acuminate, but not subulate; [collectively widespread]. |
14 Calyx distinctly bilabiate, the lower 2 lobes 1.5-2.5× longer than the upper 3 lobes, and separated from each other and the upper 3 lobes by deeper sinuses |
14 Calyx not distinctly bilabiate, all of the calyx lobes about the same length, the sinuses about the same depth. |
15 Petioles (2-) 3-15 mm long; inflorescence corymbose, loose, the branches apparent; [dry, sandy or rocky habitats]. |
16 Leaves 6-10 cm long; terminal capitula 2.5-5 cm wide in fruit; [dry rocky woodlands; sw. NC, w. SC, and southward] |
16 Leaves 4-6.5 cm long; terminal capitula 1.5-2.5 cm wide in fruit; [longleaf pine sandhills, se. GA and FL] |
15 Petioles 0-2 (-3) mm long; inflorescence capitate, tight, the branches within the clusters not apparent; [moist habitats, widespread]. |
17 Calyx lobes attenuate, with stiff hairs usually extending beyond the apex; anthers nonfunctional, included; stems with long hairs (0.1-0.6 mm long), clearly hairy to the naked eye |
17 Calyx lobes deltoid, with flexuous hairs not or barely extending beyond the apex; anthers functional, exserted; stems glabrate or with short puberulence (0.1 mm or less long), appearing glabrous to the naked eye |
12 Calyx lobes usually tipped with a tuft of long, jointed bristles. |
18 Calyx not distinctly bilabiate, all of the calyx lobes about the same length, the sinuses about the same depth. |
19 Longer calyx lobes 1-2 mm long; [Mountains] |
19 Longer calyx lobes 2.5-3 mm long; [Coastal Plain] |
18 Calyx distinctly bilabiate, the lower 2 lobes 1.5-2.5× longer than the upper 3 lobes, and separated from each other and the upper 3 lobes by deeper sinuses. |
20 Leaves lanceolate, (10-) 15-25 mm wide, > 3× as long as wide |
20 Leaves ovate, 13-50 mm wide, < 3× as long as wide. |
21 Leaves of the lower and middle stem with lower surfaces glabrate, glandular- punctate, similar in color to the dark green upper surface; calyx 5-7 mm long |
21 Leaves of the lower and middle stems with lower surface canescent, distinctly paler than the dark green upper surface; calyx 3-6.5 mm long. |
22 Calyx lobes broadly triangular, their apices obtuse, acute, or somewhat acuminate; calyx tube > 2× as long as the longest (lower) calyx lobes. |
23 Pubescence of the stem of dense, very small downwardly-curved hairs, usually mixed with scattered longer and spreading hairs |
23 Pubescence of the stem of sparse, coarse, downwardly-curved hairs |
22 Calyx lobes narrowly triangular, their apices acuminate to attenuate; calyx tube 1-2× as long as the longest (lower) calyx lobes. |
24 Mericarps 0.5-1.3 mm long, with a smooth surface, glabrous or with a few short hairs at the tip |
24 Mericarps 1.2-1.5 mm long, with a rugose or pitted surface, densely pubescent at the tip. |
25 Stems and lower leaf surfaces canescent, the short hairs often intermixed with longer, spreading ones |
25 Stems and lower leaf surfaces with coarse, spreading hairs only |