Oenothera cespitosa
Cat. Pl. Upper Louisiana, no. 53. 1813.
Herbs perennial, acaulescent or caulescent, usually hirsute or villous, usually also glandular puberulent, or exclusively strigillose, rarely glabrous; from stout taproot, sometimes lateral roots producing adventitious shoots. Stems (when present), usually ascending or decumbent, unbranched or branched from near base, 0–40 cm. Leaves 1.7–26 (–36) × (0.3–) 0.5–4.5 (–6.5) cm; petiole (0.2–) 1.7–11 (–14) cm; blade usually oblanceolate to rhombic or spatulate, rarely elliptic, obovate, lanceolate, or linear-oblanceolate, margins irregularly sinuate-dentate, serrate, pinnatifid, lobed, or subentire, apex usually acute to rounded, rarely acuminate. Flowers 1–4 (–6) per stem opening per day near sunset, with moderate to strong sweet scent with a rubbery background scent; buds usually erect, rarely recurved (during early development); floral-tube (20–) 40–140 (–165) mm; sepals (15–) 18–45 (–54) mm; petals white, fading rose or rose-pink to dark or deep rose-purple, or pink to pale or light rose, or lavender, obovate or obcordate, (16–) 20–50 (–60) mm; filaments (6–) 10–30 (–35) mm, anthers (6–) 9–17 (–20) mm; style (45–) 60–180 (–185) mm, stigma exserted beyond anthers at anthesis. Capsules straight, curved, falcate, or sigmoid, usually cylindrical to lanceoloid or ellipsoid, sometimes ovoid, usually obtusely 4-angled, (10–) 13–50 (–68) × 4–9 mm, tapering to a sterile beak 6–8 mm, valve margins with rows of distinct tubercles to sinuate or nearly smooth ridges, dehiscent 1/3–7/8 their length; pedicel (0–) 1–40 (–55) mm. Seeds numerous in 1 or 2 rows per locule, usually obovoid, oblong, or triangular, rarely suborbicular, 2.1–3.9 × 1–2.6 mm, embryo 1/5–2/3 of seed volume, surface papillose, reticulate or rarely irregularly roughened; seed collar sealed by a thin membrane, this flat or depressed into raphial cavity, when depressed often splitting, becoming separated from seed collar. 2n = 14, 28.
Distribution
w North America, nw Mexico
Discussion
Subspecies 5 (5 in the flora).
Oenothera cespitosa occurs in a wide array of habitats, from grassland, desert scrub, pinyon-juniper woodland, or Arizona chaparral to montane conifer forests, rarely at timberline, at elevations from (450–)800–3370 m. Oenothera cespitosa is self-incompatible (W. L. Wagner et al. 1985; Wagner 2005).
Pachylophus nuttallii Spach is an illegitimate name that pertains here.
Selected References
None.
Lower Taxa
Key
| 1 | Plants glabrous. | > 2 |
| 2 | Floral tubes (28–)35–60(–85) mm; petals fading rose pink to dark rose purple; capsules falcate or sigmoid, valve margins tuberculate. | Oenothera cespitosa subsp. cespitosa |
| 2 | Floral tubes (45–)75–110(–153) mm; petals fading pink or rarely pale rose; capsules somewhat curved, valve margins with smooth to irregular, undulate ridges. | Oenothera cespitosa subsp. macroglottis |
| 1 | Plants hirsute, villous, glandular puberulent, or strigillose. | > 3 |
| 3 | Plants strigillose, rarely glandular puberulent; petals fading rose pink to dark rose purple. | Oenothera cespitosa subsp. cespitosa |
| 3 | Plants hirsute or villous, usually also glandular puberulent, rarely only glandular puberulent; petals fading pink to light or pale rose or lavender-rose, sometimes deep rose purple. | > 4 |
| 4 | Stems unbranched to many-branched, sometimes producing dense clumps 5–50 cm diam.; petals fading rose; seed collar sinuate distally. | Oenothera cespitosa subsp. crinita |
| 4 | Stems unbranched to several-branched, not forming clumps; petals fading rose purple or pink to pale rose or lavender; seed collar various. | > 5 |
| 5 | Petals fading rose or sometimes deep rose purple; capsules ellipsoid to lanceoloid-ellipsoid, falcate or sigmoid; pedicels 0.5–1 mm; seed collar membrane depressed and often splitting at maturity, margin conspicuously sinuate throughout. | Oenothera cespitosa subsp. crinita |
| 5 | Petals fading pink to pale rose or lavender; capsules lanceoloid to cylindrical, straight or somewhat curved; pedicels usually (0–)1–40(–55) mm; seed collar membrane neither depressed nor splitting at maturity, margin not sinuate, sometimes somewhat so distally. | > 6 |
| 6 | Capsules oblong-lanceoloid; buds often recurved when young; floral tube (35–)40–70(–80) mm; plants shaggy-villous, sometimes densely so. | Oenothera cespitosa subsp. navajoensis |
| 6 | Capsules cylindrical to lanceoloid-cylindrical; buds erect; floral tube (41–)75–140-(–165) mm; plants hirsute. | > 7 |
| 7 | Capsules somewhat curved, valve margins with nearly smooth to irregular, undulate ridges; leaf blades oblanceolate to spatulate, margins dentate. | Oenothera cespitosa subsp. macroglottis |
| 7 | Capsules straight, valve margins with minute to conspicuous tubercles, these sometimes coalesced into a sinuate ridge; leaf blades usually oblanceolate to narrowly elliptic, rarely lanceolate, margins usually pinnately lobed to dentate, rarely serrate. | Oenothera cespitosa subsp. marginata |