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See list of 9 species in this genus

References: Wherry (1929, 1930, 1931).

  • 1a. Petals notched at apex [Fig. 781]; leaf blades stiff, with a single primary vein; stems suffrutescent
    • 2a. Leaf blades (15–) 20–40 (–60) mm long; axillary fascicles mostly lacking; apical sinus of petal 0.25–0.5 times as long as entire petal
    • 2b. Leaf blades (5–) 8–20 mm long; axillary fascicles usually present and conspicuous [Fig. 781]; apical sinus of petal 0.12–0.25 times as long as entire petal
  • 1b. Petals entire at the apex or sometimes emarginate to shallowly notched in P. divaricata; leaf blades herbaceous, with a midvein and several primary lateral veins (though the lateral veins often faint; with only a midvein in P. pilosa); stems herbaceous
    • 3a. Style short, 1–4 mm long, scarcely (if at all) longer than the stigmas or the ovary; stamens and style at most reaching the midpoint of the basal, connate portion of corolla
      • 4a. Upper leaves alternate; corolla commonly red, white, or variegated; plants annual
      • 4b. Upper leaves opposite; corolla usually pink, blue, light blue-purple, or light red-purple ; plants perennial
        • 5a. Leaf blades linear to lanceolate or narrow-ovate, tapering to a sharp, indurate awn-tip 0.5–3 mm long; basal, connate portion of corolla usually pubescent; both the reproductive stem, as well as the sterile basal offshoots erect to ascending
        • 5b. Leaf blades elliptic or oblong to lanceolate or ovate, obtuse to acute at the apex, sometimes tapering to a short awn-tip up to 0.5 mm; basal, connate portion of the corolla glabrous; reproductive stem erect or decumbent at base, whereas the sterile, basal offshoots are prostrate and rooting
    • 3b. Style elongate, (12–) 14–26 mm long, much longer than the stigmas or the ovary; stamens and style reaching at least the orifice of the basal, connate portion of corolla
      • 6a. Long-creeping, sterile, basal offshoots with spatulate leaf blades present at anthesis; flowering stems 10–40 (–50) cm tall; inflorescence and calyx stipitate-glandular; corolla 25–30 mm wide
      • 6b. Sterile, basal offshoots absent at anthesis or present and short, upcurving, and without spatulate leaf blades; flowering stems 30–200 cm tall; inflorescence and calyx glabrous or pubescent, but not glandular; corolla 12–22 mm wide
        • 7a. Leaf blades ciliolate on the margin, with conspicuous lateral veins that 
connect near the edge to form a submarginal vein around the perimeter of the 
blade [Fig. 780]; anthers pale yellow to white
        • 7b. Leaf blades eciliate on the margin, without a submarginal, connecting vein; anthers yellow
          • 8a. Calyx 6–8 (–10) mm long; stems streaked or spotted with red (very rarely green throughout), arising from rhizomes, with 7–15 (or more) nodes below the inflorescence
          • 8b. Calyx (8.5–) 10–13 mm long; stems without red streaks or spots, arising from decumbent stems, with 3–5 nodes below the inflorescence

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 Show photos of:   Each photo represents one species in this genus.