The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links
Photo is of parent taxon
Photo is of parent taxon

cespitose evening-primrose

Habit Herbs acaulescent or short-caulescent, hirsute and glandular puberulent, or glabrous. Herbs acaulescent or caulescent, densely hirsute, also sparsely glandular puberulent.
Stems

(if present), usually unbranched, rarely with 1–several short laterals, 4–8 cm.

unbranched to many-branched, and then sometimes producing dense clumps 5–50 cm diam., 2–14 cm.

Leaves

(6.8–)9.5–23(–32) × (1.3–)2.4–4.5(–6.5) cm;

petiole (3–)4–11(–14) cm;

blade oblanceolate to spatulate, margins often undulate, usually regularly to irregularly dentate, rarely coarsely and irregularly pinnately lobed.

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 (45–)75–110(–153) mm;

sepals (22–)30–45(–50) mm;

petals fading pink to pale rose, (21–)35–43(–50) mm;

filaments (16–)19–28(–35) mm, anthers (10–)12–17 mm;

style 85–180 mm.

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

somewhat curved, lanceoloid-cylindrical to cylindrical, symmetrical throughout, sometimes slightly flattened on one side at base, (17–)25–45(–56) × 5–8 mm, valve margins with conspicuous, nearly smooth to irregular undulate ridge;

pedicel 2–7 mm.

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

narrowly obovoid, 2.5–3 × 1–1.4 mm, embryo 1/2 of seed volume, surface minutely papillose to reticulate;

seed collar forming narrow slit above raphe with a slightly sunken membrane, margin entire or obscurely sinuate distally.

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.

= 14, 28.

Oenothera cespitosa subsp. macroglottis

Oenothera cespitosa subsp. crinita

Phenology Flowering May–Jul(–Sep). Flowering Apr–Jul.
Habitat Open, igneous rocky slopes, talus, roadcuts, open or shaded and sandy or gravelly sites along streams, rarely on shale, in upper pinyon-juniper woodlands, Gambel oak scrub, ponderosa pine forests, ponderosa pine-Douglas fir forests, spruce-fir-lodgepole pine forests. 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 2000–3100 m. (6600–10200 ft.) 1100–3400 m. (3600–11200 ft.)
Distribution
from FNA
CO; NM; UT; WY
from FNA
AZ; CA; NV; UT
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.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Pachylophus > Oenothera cespitosa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Pachylophus > Oenothera cespitosa
Sibling taxa
O. cespitosa subsp. cespitosa, O. cespitosa subsp. crinita, O. cespitosa subsp. marginata, O. cespitosa subsp. navajoensis
O. cespitosa subsp. cespitosa, O. cespitosa subsp. macroglottis, O. cespitosa subsp. marginata, O. cespitosa subsp. navajoensis
Synonyms Pachylophus macroglottis, O. cespitosa var. macroglottis, P. hirsutus Pachylophus crinitus, O. cespitosa var. crinita, O. cespitosa subsp. jonesii, O. cespitosa var. jonesii, O. cespitosa var. stellae
Name authority (Rydberg) W. L. Wagner, Stockhouse & W. M. Klein: Ann. Missouri Bot. Gard. 70: 195. (1983) — (as caespitosa) (Rydberg) Munz in N. L. Britton et al.: N. Amer. Fl., ser. 2, 5: 100. (1965) — (as caespitosa)
Web links