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Photo is of parent taxon

fragrant evening-primrose

Photo is of parent taxon
Habit Herbs caulescent or acaulescent, usually moderately to densely hirsute and glandular puberulent, rarely exclusively glandular puberulent. Herbs caulescent or acaulescent, moderately to densely crinkly-villous (often appearing shaggy), and glandular puberulent.
Stems

usually unbranched, rarely with 1–several branches from near base, 10–40 cm.

(if present) unbranched to few-branched, (0–)10–25 cm.

Leaves

(2.8–)10–26(–36) × (0.6–)1–3(–4.5) cm;

petiole (3–)4–11(–14) cm;

blade usually oblanceolate to narrowly elliptic, rarely lanceolate, margins coarsely and irregularly pinnately lobed to dentate or, rarely, serrate.

(3.5–)4–13(–16) × (0.7–)1–3.2 cm;

petiole (1.3–)1.7–10(–12) cm;

blade oblanceolate to rhombic-obovate, margins often coarsely and irregularly dentate or serrate, sometimes pinnately lobed, often with several larger lobes near blade base.

Flowers

floral tube (41–)80–140(–165) mm;

sepals (22–)34–45(–54) mm;

petals fading pink to lavender, (24–)35–50(–60) mm;

filaments (16–)20–30(–35) mm, anthers (10–)12–17(–20) mm;

style (78–)100–150(–185) mm.

buds often recurved when young;

floral tube (35–)40–70(–80) mm;

sepals 22–27(–32) mm;

petals fading pink to light rose, (25–)28–32(–34) mm;

filaments 11–15(–17) mm, anthers 9–12 mm;

style (50–)59–85(–96) mm.

Capsules

straight, cylindrical to, sometimes, lanceoloid-cylindrical, slightly asymmetrical, (21–)25–50(–68) × 6–8 mm, valve margins with minute to conspicuous tubercles, these sometimes coalesced into a sinuate ridge;

pedicel (0–)1–40(–55) mm.

straight, oblong-lanceoloid, base asymmetrical, 13–35(–40) × 5–6 mm;

valve margins with a low sinuate ridge to 8–15 small, nearly distinct tubercles;

pedicel 1–3 mm.

Seeds

usually narrowly to broadly obovoid, rarely suborbicular, 2.2–3.4 × 1.1–2.6 mm, embryo 1/5–1/2 of seed volume, surface appearing longitudinally striate, reticulate under magnification;

seed collar large, usually appearing inflated, sealed by a flat membrane which is often slightly depressed into seed collar cavity, margin entire or obscurely sinuate distally.

narrowly obovoid, 2.1–2.6 × 1.1–1.3 mm, embryo 1/2 of seed volume, surface minutely papillose;

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

2n

= 14.

= 14, 28.

Oenothera cespitosa subsp. marginata

Oenothera cespitosa subsp. navajoensis

Phenology Flowering Mar–Aug. Flowering (Apr–)May–Jun.
Habitat Rocky slopes, cracks in rocks, talus, along gravelly creek beds and arroyos, roadcuts in loose to somewhat compacted soil derived from granite, sandstone, limestone, volcanic cinder, rarely shale, mostly in foothill communities of pinyon-juniper woodlands, big sagebrush scrub, chaparral, grass­lands, openings in ponderosa pine forests. Colorado Plateau region, forming small colonies on loose or compacted soil derived from clay, shale, fine-textured sandstone, or gypsum, on slopes and along small drainage patterns, often around harvester ant mounds, arroyos in somewhat sandy or gravelly soil, in shrubby commu­nities dominated by Atriplex confertifolia, A. corrugata, A. cuneata, Artemisia spinescens, Coleogyne ramosissima, Frankenia jamesii, Hilaria jamesii, with big sagebrush scrub or sage-grasslands, rarely in lower pinyon-juniper woodlands.
Elevation (400–)1200–2300(–3100) m. ((1300–)3900–7500(–10200) ft.) 1100–1900(–2100) m. (3600–6200(–6900) ft.)
Distribution
from FNA
AZ; CA; CO; ID; NM; NV; OR; TX; UT; WA; WY; Mexico (Chihuahua, Sonora)
from FNA
AZ; CO; NM; UT
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. macroglottis, O. cespitosa subsp. navajoensis
O. cespitosa subsp. cespitosa, O. cespitosa subsp. crinita, O. cespitosa subsp. macroglottis, O. cespitosa subsp. marginata
Synonyms O. marginata, Anogra longiflora, O. cespitosa subsp. eximia, O. cespitosa var. eximia, O. cespitosa var. longiflora, O. cespitosa var. marginata, O. eximia, O. idahoensis, Pachylophus cylindrocarpus, P. exiguus, P. eximius, P. longiflorus, P. marginatus, P. prolatus O. cespitosa var. navajoensis, Pachylophus caulescens
Name authority (Nuttall ex Hooker & Arnott) Munz in N. L. Britton et al.: N. Amer. Fl., ser. 2, 5: 101. (1965) — (as caespitosa) W. L. Wagner, Stockhouse & W. M. Klein: Monogr. Syst. Bot. Missouri Bot. Gard. 12: 66, fig. 104. (1985) — (as caespitosa)
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