Oenothera macrocarpa |
Oenothera coloradensis |
|||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
bigfruit evening primrose, Missouri evening primrose, Ozark sundrop |
Colorado beeblossom |
|||||||||||||||||
Habit | Herbs caulescent, strigillose or glabrous, sometimes glandular puberulent distally; from a stout taproot, sometimes lateral roots producing adventitious shoots. | Herbs monocarpic perennial, strigillose proximally, short-hirtellous and strigillose distally, leaves sometimes glabrate; from stout, fleshy taproot. | ||||||||||||||||
Stems | moderately leafy, (1–)4–40(–60) cm. |
1–few-branched from base, 50–80(–100) cm. |
||||||||||||||||
Leaves | cauline, (2.8–)3.7–12.5(–17) × (0.1–)0.4–3(–4.5) cm; petiole (0.4–)1–4(–6) cm; blade linear, lanceolate-elliptic, elliptic to oblanceolate or suborbiculate, margins entire or conspicuously or inconspicuously denticulate or serrulate, sometimes undulate, apex usually acute, sometimes obtuse or retuse (subsp. incana). |
in a basal rosette and cauline, basal 4–18 × 1.5–4 cm, blade very narrowly elliptic, lanceolate, or oblanceolate; cauline 5–13 × 1–4 cm, blade narrowly elliptic, narrowly lanceolate, or narrowly oblanceolate, margins subentire or repand-denticulate. |
||||||||||||||||
Flowers | usually 1 or 2, rarely more, opening per day near sunset, fading next morning, sometimes (subspp. |
4-merous, zygomorphic, opening at sunset; floral tube 8–12 mm; sepals 9.5–13 mm; petals white, fading pink, rhombic-obovate, 7–12 mm; filaments 6.5–9 mm, anthers 2.5–4 mm, pollen 90–100% fertile; style 19–25 mm, stigma exserted beyond anthers at anthesis. |
||||||||||||||||
Capsules | papery in age, narrowly ellipsoid to lanceoloid, sometimes twisted (subsp. fremontii), winged, wings (2–)10–28(–34) mm wide, body (13–)25–70(–115) × 2–9 mm, dehiscent 1/4–1/3 their length; pedicel 1–12(–25) mm. |
ellipsoid or ovoid, sharply 4-angled, with fairly deep furrows alternating with angles, 6–8.5 × 2–3 mm; sessile. |
||||||||||||||||
Seeds | numerous, rarely as few as 8, in 1 row per locule, obovoid, (2–)3–5 × 1–2.3 mm. |
1–4, yellowish to light brown, 2–3 × 1 mm. |
||||||||||||||||
Macrocarpa | and oklahomensis) lasting for 2 days, weakly scented; buds with unequal free tips 1–11(–15) mm; floral tube (21–)35–140(–160) mm; sepals (20–)25–65(–75) mm; petals bright yellow, fading orange, reddish orange or mostly unchanged, obovate to very broadly obovate, (17–)25–65(–68) mm, usually with terminal notch and/or tooth, margin sometimes erose; filaments 13–40(–44) mm, anthers 10–24(–25) mm; style (45–)55–192 mm, stigma usually exserted beyond anthers at anthesis. |
|||||||||||||||||
2n | = 14. |
|||||||||||||||||
Oenothera macrocarpa |
Oenothera coloradensis |
|||||||||||||||||
Phenology | Flowering Jul–Sep. | |||||||||||||||||
Habitat | In wet meadow vegetation of North and South Platte River watersheds on high plains, sloping floodplains, drainage basins in heavy soil. | |||||||||||||||||
Elevation | 1500–2000 m. (4900–6600 ft.) | |||||||||||||||||
Distribution |
c United States; n Mexico; s United States
|
CO; NE; WY |
||||||||||||||||
Discussion | Subspecies 5 (4 in the flora). Oenotheramacrocarpa is variable and has differentiated extensively in the Great Plains region. Each of the five distinctive subspecies occupies a different geographical and ecological situation. Only subsp. mexicana W. L. Wagner from Coahuila, Mexico, occurs outside of the flora area. In general, the subspecies are sharply distinct and each is characterized by a number of features, including pubescence, leaf features, flower and floral tube size, and size and morphology of the capsules and seeds. The five entities are treated as subspecies primarily because of their complete interfertility and extensive intergradation in any area of marginal contact. Intermediates are known between subsp. macrocarpa and subspp. fremontii and oklahomensis and between subspp. incana and oklahomensis. There is also some evidence that suggests past hybridization between subspp. fremontii and incana although there is no present contact between them. All subspecies are self-incompatible. Oenothera alata Nuttall (1818) is an illegitimate name based on O. macrocarpa and pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera coloradensis is currently known from fewer than two dozen populations from southern Laramie and Platte counties in Wyoming, northern Weld County, Colorado, formerly near Fort Collins, Larimer County, Colorado, and in western Kimball County, Nebraska. It is federally listed as a threatened species in the United States. The primary threats are agricultural use of habitat, herbicide spraying to control weed species, and livestock trampling and grazing (see W. L. Wagner et al. 2013). Recent study by K. N. Krakos (unpubl.) has determined this species to be self-compatible. P. H. Raven and D. P. Gregory (1972[1973]) described this species as glandular puberulent in inflorescence, which was repeated in the recent revised taxonomy (Wagner et al.); however, examination of specimens show that P. A. Munz (1965) was correct in describing the pubescence of the inflorescence as non-glandular. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||||||||||
Key |
|
|||||||||||||||||
Source | FNA vol. 10. | FNA vol. 10. | ||||||||||||||||
Parent taxa | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Megapterium | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Gaura > subsect. Gaura | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Synonyms | Megapterium macrocarpum, M. nuttallianum | Gaura coloradensis, G. neomexicana subsp. coloradensis, G. neomexicana var. coloradensis | ||||||||||||||||
Name authority | Nuttall: Cat. Pl. Upper Louisiana, no. 56. (1813) | (Rydberg) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 211. (2007) | ||||||||||||||||
Web links |