Oenothera macrocarpa
Oenothera wolfii
bigfruit evening primrose, Missouri evening primrose, Ozark sundrop
Wolf's evening-primrose
moderately leafy, (1–)4–40(–60) cm.
erect, green, flushed with red proximally or red throughout, unbranched or branches obliquely arising from rosette and sometimes secondary branches arising from main stem, 50–100 cm.
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 13–35 ×1.5–4(–5) cm, cauline 5–18 × 1–2.5(–4) cm;
blade dull green, flat, oblanceolate to narrowly lanceolate or lanceolate to elliptic, margins bluntly dentate or subentire, teeth widely spaced or sinuate proximally;
bracts persistent.
erect, unbranched.
usually 1 or 2, rarely more, opening per day near sunset, fading next morning, sometimes (subspp.
opening near sunset;
buds erect, 5–8 mmdiam., with free tips terminal, erect, 1–3 mm;
floral tube 30–46 mm;
sepals yellowish green, also usually flushed with red or red-striped, 17–28 mm;
petals yellow, fading orange, pale yellow and somewhat opaque, very broadly obcordate, 13–23 mm, conspicuously shorter than sepals;
filaments 12–20 mm, anthers 7–12 mm, pollen ca. 50% fertile;
style 43–58 mm, stigma usually slightly exserted beyond anthers or surrounded by them at anthesis.
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.
erect or slightly spreading, dark dull green and sometimes red-striped when dry, narrowly lanceoloid, 30–48 × 5–7 mm, free tips of valves 0.5–2.5mm.
numerous, rarely as few as 8, in 1 row per locule, obovoid, (2–)3–5 × 1–2.3 mm.
0.9–2 × 0.9–1.3 mm.
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.
= 14.
Oenothera macrocarpa
Oenothera wolfii
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 wolfii is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous (W. Dietrich et al. 1997). It has plastome I and a AA genome composition. It is known only from the vicinity of Port Orford, Curry County, Oregon (currently apparently only as far north as Otter Rock), south in a scattered distribution through Del Norte County to the mouth of the Mattole River, Humboldt County, California. The distribution, at least in California, is closely associated with small patches of Cenozoic-age marine sediments, isolated from each other by Franciscan sedimentary and metamorphic rocks. Most populations appear to occur near river mouths or to the south of a headland. The largest populations center in the area about 11 km long in the vicinity of Crescent City in Del Norte County, between Point George and Enderts Beach in Redwood National Park. There are collections from two inland California localities, one at the eastern border of Humboldt County, California (Willow Creek, Trinity River Valley), and the other at Carville, Trinity County, that may be O. wolfii. If so, they would presumably represent recent introductions and should be studied further. As summarized by Dietrich et al., O. wolfii is a rare endemic of coastal habitats and known from about 20 different sites. The total number of individuals of O. wolfii apparently fluctuates, with perhaps no more than about 5000 individuals total. It is threatened by any potential development and alteration of its habitat, presently by road maintenance and foot traffic. Another possibly more serious threat comes from the recent spread of O. glazioviana to this area. Oenothera glazioviana could swamp populations through hybridization and, perhaps, by direct competition.
Oenothera wolfii is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Herbs glabrous. | → 2 |
2. Leaf blades usually very broadly elliptic to suborbiculate, rarely oblanceolate or elliptic, 2–4.3 cm wide, margins usually entire, sometimes inconspicuously denticulate, usually flat, sometimes undulate. | subsp. incana |
2. Leaf blades usually elliptic to lanceolate-elliptic, sometimes linear, (0.3–)0.8–2(–3) cm wide, margins usually conspicuously denticulate to serrulate, rarely subentire, usually undulate. | subsp. oklahomensis |
1. Herbs strigillose. | → 3 |
3. Bud free tips 1–2(–5) mm; petals (17–)25–33(–37) mm; floral tubes (21–)35–65(–80) mm; capsules often twisted, 13–30(–65) mm, wings 2–5(–9) mm wide. | subsp. fremontii |
3. Bud free tips (4–)5–11(–12) mm; petals (25–)31–65(–68) mm; floral tubes (50–)70–140(–160) mm; capsules not twisted, (28–)30–70(–115) mm, wings 10–28(–34) mm wide. | → 4 |
4. Leaves green or younger ones grayish green, moderately strigillose, rarely more densely strigillose, blades often lanceolate-elliptic to broadly elliptic, sometimes linear or lanceolate, 0.4–2.3(–3) cm wide; capsule wings (14–)18–28(–34) mm wide. | subsp. macrocarpa |
4. Leaves gray, densely strigillose, blades very broadly elliptic to suborbiculate, rarely oblanceolate or elliptic, 2–4.3 cm wide; capsule wings 10–15(–24) mm wide. | subsp. incana |
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