Oenothera macrocarpa
Oenothera heterophylla
bigfruit evening primrose, Missouri evening primrose, Ozark sundrop
variableleaf evening primrose
moderately leafy, (1–)4–40(–60) cm.
unbranched or branched mainly in distal part, 25–70 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 7–15 × 1–2.5 cm, cauline 3–13 ×0.4–2.3 cm;
blade narrowly oblanceolate to oblanceolate, gradually narrowly lanceolate to lanceolate or elliptic distally, margins deeply lobed to remotely dentate or subentire;
bracts longer than capsule they subtend, 1–3 cm.
dense, often with several lateral branches, mature buds usually overtopping spike apex.
usually 1 or 2, rarely more, opening per day near sunset, fading next morning, sometimes (subspp.
2–several per spike opening per day near sunset;
buds erect, with free tips erect or spreading, 1–6 mm;
floral tube nearly straight, 25–47 mm;
sepals 15–30 mm;
petals yellow, broadly elliptic to nearly rhombic, 18–35 mm;
filaments 15–30 mm, anthers 3–8 mm, pollen 85–100% fertile;
style 45–75 mm, stigma usually exserted beyond anthers 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.
lanceoloid, 13–25 × 2.5–4 mm.
numerous, rarely as few as 8, in 1 row per locule, obovoid, (2–)3–5 × 1–2.3 mm.
brown, often flecked with darker spots, ellipsoid to broadly ellipsoid, 1.1–1.8 × 0.4–0.8 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.
Oenothera macrocarpa
Oenothera heterophylla
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.)
Subspecies 2 (2 in the flora).
(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 |
1. Herbs densely to sparsely strigillose, also at least parts of inflorescence sparsely hirsute with spreading, pustulate-based hairs, and often glandular puberulent and villous; flower buds with free tips spreading, 2–6 mm. | subsp. heterophylla |
1. Herbs densely to sparsely strigillose, also at least part of inflorescence glabrate or glandular puberulent; flower buds with free tips erect, 1–3 mm. | subsp. orientalis |
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