Flora of North America species comparison

central stem usually erect, usually thickened at base and spongy, branched or unbranched, branches few–several, slender, decumbent to ascending, from base, usually encircling central stem in older plants, 10–40(–100) cm.

erect, several-branched near ground, also branched proximal to inflorescences, 60–280 cm.

in a basal rosette and cauline, rosette usually well developed (except subsp. howellii), basal 5–25 × 1–5 cm, cauline 4–12(–18) × 0.5–4 cm;

petiole 1.5–8 cm;

blade rhombic-obovate, lanceolate, or oblanceolate, margins subentire, dentate, or pinnatifid.

in a basal rosette and cauline, 0.5–8 × 0.15–2 cm, sessile, blade narrowly lanceolate or oblanceolate to very narrowly elliptic or linear, margins usually subentire or shallowly sinuate-dentate, sometimes deeply sinuate-dentate, often undulate.

slender.

1–several opening per day near sunset;

buds nodding, weakly or strongly quadrangular or fluted in distal 1/2, with free tips 0–9 mm;

floral tube 20–40 mm;

sepals (13–)15–35 mm, not spotted;

petals white, fading pink to deep pink, broadly obovate or obcordate, 15–44 mm;

filaments 8–15 mm, anthers 5–14 mm;

style 35–60 mm, stigma exserted beyond anthers at anthesis.

4-merous, zygomorphic, opening near sunset;

floral tube 1.5–5 mm;

sepals 6–14 mm;

petals white, fading pink to red, slightly unequal, elliptic, 7–13 mm, clawed;

stamens presented in lower 1/2 of flower, filaments 4.5–11 mm, anthers 2–4.5 mm, pollen 90–100% fertile;

style 9–19 mm, stigma exserted beyond anthers at anthesis.

spreading, straight to curved, becoming somewhat woody in age, cylindrical to slightly 4-angled, widest toward base, tapering from base to apex, (15–)30–80 × 1.5–5 mm;

sessile.

lanceoloid to narrowly ovoid, 4-winged, 9–19 × 1–3.5 mm, abruptly constricted to a long, sterile stipe 2–10 mm.

numerous, in 1 row per locule, buff with dark spots or black, narrowly obovoid, 1.5–2.8 mm.

(1 or)2–4, 2–3(–4) × 0.8–1.3 mm, yellowish to light brown or rarely reddish brown.