Oenothera filiformis
Oenothera villosa
bee-blossom, longflower beeblossom
hairy evening-primrose, villous evening primrose, yellow evening-primrose
usually well-branched distal to base, (50–)100–400 cm.
erect, usually flushed with red proximally, sometimes green or red throughout, unbranched or with branches obliquely arising from rosette and secondary branches arising from main stem, 50–200 cm.
in a basal rosette and cauline, basal 8–15(–40) × 1.5–3.6 cm, blade lyrate, margins irregularly toothed to lobed;
cauline 1.5–13 × 0.5–3 cm, blade narrowly elliptic to elliptic or lanceolate, margins subentire or shallowly undulate-denticulate.
in a basal rosette and cauline, basal 10–30 × 1.2–4(–5) cm, cauline 5–20 × 1–2.5(–4) cm;
blade dull green or grayish green, narrowly oblanceolate, oblanceolate to narrowly elliptic, or narrowly lanceolate, margins flat or undulate, dentate to subentire, teeth sometimes widely spaced, sometimes sinuate-dentate proximally;
bracts persistent.
dense to open, erect, unbranched.
4-merous, zygomorphic, opening at sunset;
floral tube 4–13(–15) mm;
sepals 7–18 mm;
petals white, fading pink, elliptic to elliptic-obovate, 7–15 mm;
filaments 5–13 mm, anthers 1.5–5 mm, pollen 90–100% fertile;
style 12–34 mm, stigma exserted beyond anthers at anthesis.
opening near sunset;
buds erect, 3–5 mm diam., with free tips terminal, erect, 0.5–3 mm;
floral tube 23–44 mm;
sepals green to yellowish green, red-striped, or flushed with red, 9–18 mm;
petals yellow to pale yellow, fading orange or pale yellow, very broadly obcordate, 7–20 mm;
filaments 7–15 mm, anthers 4–10 mm, pollen ca. 50% fertile;
style 30–55 mm, stigma surrounded by anthers at anthesis.
ellipsoid or ovoid, sharply 4-angled, 4.5–7 × 1.5–2.5 mm;
sessile.
erect or slightly spreading, dull green or gray-green when dry, lanceoloid, 20–43 × 4–7 mm, free tips of valves 1–2 mm.
2–4, yellowish to reddish brown, 1.3–3 × 0.7–1.3 mm.
1–2 × 0.5–1.2 mm.
= 14.
Oenothera filiformis
Oenothera villosa
P. H. Raven and D. P. Gregory (1972[1973]) found various levels of hybridization and intergradation between Oenothera filiformis and O. lindheimeri to occur where their ranges overlap. In the region of geographical overlap, most populations of O. filiformis are strigillose in the inflorescences and have evening-opening flowers, while O. lindheimeri is villous in the inflorescences, and has large morning-opening flowers. Moreover, O. lindheimeri occurs only on black clay prairie soil, while O. filiformis occurs in light, sandy soil, as it does throughout its range, and in more disturbed areas. Despite these differences, Raven and Gregory found hybridization between these species scattered across an area from eastern Texas across Louisiana to Alabama. At some locations there is apparently no hybridization, while at others hybrids were uncommon to relatively common. Intermediate morning-blooming plants in Alabama appear to represent evidence of past hybridization since O. lindheimeri does not occur there. Many of the individuals they tested had somewhat reduced pollen fertility (40–70% fertile). They suspected that habitat disturbance was primarily responsible in many cases, but they also detected what may have been intergradation resulting from past hybridization outside of the current distribution of O. lindheimeri. Many of these individual cases deserve further investigation to better understand the dynamics of the interactions between these species and if any of the interactions have led to stabilization of novel populations that might be recognized taxonomically.
Very few collections have been made from areas on the periphery of the range of Oenothera filiformis (southern Ontario, Connecticut, Maryland, Massachusetts, Pennsylvania), and populations in these areas probably represent recent human-based introductions. P. H. Raven and D. P. Gregory (1972[1973]) determined O. filiformis to be self-incompatible.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Subspecies 2 (2 in the flora).
Oenothera villosa is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous with plastome I and a AA genome composition (W. Dietrich et al. 1997). The original natural range of O. villosa was presumably from southern British Columbia south to California and east through the Rocky Mountain and the Great Plains regions. The wide occurrence east of this area in North America to eastern Quebec south throughout most of the eastern half of the United States, except for extreme southern and southeastern parts, is most likely the result of recent spread of this species, probably in the past several hundred years. Oenothera villosa is subdivided into two subspecies: subsp. strigosa occurs primarily in the Pacific Northwest southeast through the Rocky Mountains; subsp. villosa is found primarily from the eastern foothills of the Rocky Mountains eastward throughout the Great Plains region. Both taxa occur sporadically beyond these regions, and subsp. villosa is naturalized in many parts of the world.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Inflorescences usually dense (internodes in fruit usually shorter than capsule); plants dull green to grayish green, densely strigillose and sometimes also sparsely villous with appressed or subappressed hairs, these without or with red or green pustulate bases, rarely sparsely glandular puberulent distally; sepals green to yellowish green; leaf blade margins conspicuously dentate, venation prominent, especially abaxially. | subsp. villosa |
1. Inflorescences usually open (internodes in fruit usually as long as or longer than capsule); plants flushed with red at least proximally, often red throughout, strigillose, usually also villous with erect to sometimes appressed hairs with pustulate bases, pustules red, also glandular puberulent at least distally; sepals red-striped or flushed with red; leaf blade margins usually denticulate or subentire, sometimes moderately dentate, venation not prominent. | subsp. strigosa |
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