Oenothera cespitosa subsp. crinita

Herbs acaulescent or caulescent, densely hirsute, also sparsely glandular puberulent. Stems unbranched to many-branched, and then sometimes producing dense clumps 5–50 cm diam., 2–14 cm. Leaves 1.7–10(–18) × (0.3–)0.5–2.5(–3.4) cm; petiole (0.2–)3–5(–8) cm; blade usually oblanceolate to linear-oblanceolate, rarely obovate, margins subentire, sinuate, or dentate to pinnatifid. Flowers: floral tube (28–)35–75(–85) mm; sepals (15–)18–25(–27) mm; petals fading rose or sometimes deep rose purple, (16–)20–30(–35) mm; filaments (6–)10–17(–20) mm, anthers 6–8(–10) mm; style (45–)60–90(–105) mm. Capsules usually falcate or sigmoid, especially when young, also somewhat flattened, ellipsoid-ovoid to lanceoloid, 10–31(–34) × 4–9 mm, valve margins with 8–15 tubercles or these coalesced into a sinuate ridge; pedicel 0.5–1 mm. Seeds obovoid, oblong, or ± triangular, 2.9–3.5 × 1.1–2 mm, embryo 1/2–2/3 of seed volume, surface papillose, reticulate or very minutely roughened; seed collar membrane depressed and often splitting, becoming separated from collar at maturity, margin conspicuously sinuate throughout, surface often ribbed, ribs forming partial or complete vertical partitions in collar. 2n = 14, 28.

Phenology: Flowering Apr–Jul.
Habitat: Open sites, compacted or loose soil derived from dolomite, limestone, tufa, or marble, exposed knolls, gravelly benches, steep slopes, scree, rocky mesas, rocky arroyos, from mountain summits in alpine or subalpine communities with Pinus longaeva and P. flexilis or pinyon-juniper woodlands to Great Basin or Mojave Desert shrub communities dominated by Artemisia, Atriplex confertifolia, Coleogyne, Hilaria, Lycium.
Elevation: 1100–3400 m.

Distribution

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Ariz., Calif., Nev., Utah.

Discussion

Subspecies crinita is the most polymorphic subspecies of Oenothera cespitosa; it is also the least understood. W. L. Wagner et al. (1985) grouped two series of populations that appear to intergrade together within the limits of this subspecies. One population is a morphologically relatively uniform form characterized by a many-branched habit, which may form dense clumps to 50 cm diameter, leaves that are 2–7 cm, floral tubes 25–60 mm and petals that fade to a rose color, and it occurs at high elevations on rocky, lime­stone sites or at lower elevations on extreme, chalky, white limestone and dolomite substrates or sometimes scree slopes. A more common form occurs at low to mid elevations in pinyon-juniper woodlands to Great Basin or Mojave Desert scrub on rocky slopes, talus, or along arroyos that is much less compact with one to several clustered rosettes, rarely more, with leaves 8–16 cm, floral tubes 45–75 mm, and petals that fade rose purple. The common form also grows on lime­stone and dolomite but, unlike the clumped form, it does not seem to be restricted to it. To compound the problem, many foothill and valley populations of subsp. crinita intergrade extensively with subspp. cespitosa and marginata.

Selected References

None.

Lower Taxa

None.