Oenothera linifolia |
Oenothera clelandii |
|
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threadleaf evening-primrose, threadleaf sundrop |
Cleland's evening primrose |
|
Habit | Herbs annual, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot. | Herbs biennial, densely to sometimes sparsely strigillose, or also sparsely glandular puberulent distally. |
Stems | unbranched or with many ascending branches arising near base, erect, 10–50 cm. |
sometimes with lateral branches arising obliquely from rosette, 20–70(–100) cm. |
Leaves | in a basal rosette and cauline, basal 1–2(–4) × 0.2–0.6 cm, petiole 0.2–1(–1.5) cm, blade ovate to obovate or narrowly elliptic; cauline 1–4 × less than 0.1 cm, sessile, blade linear or filiform. |
in a basal rosette and cauline, basal 5–16 × 0.5–1.5 cm, cauline 2–12 × 0.5–2 cm; blade narrowly oblanceolate, gradually narrowly elliptic to narrowly lanceolate distally, margins lobed to remotely dentate or subentire; bracts slightly longer than capsule they subtend. |
Inflorescences | dense, without lateral branches, mature buds usually not overtopping spike apex. |
|
Flowers | usually 1–3 opening per day near sunrise; buds without free tips; sepals 1.5–2 mm; petals bright yellow, fading pink, obcordate to obovate, 3–5(–7) mm; filaments 1–2 mm, anthers 0.5–1 mm; style 1–2 mm, stigma surrounded by anthers at anthesis. |
2–several per spike opening per day near sunset; buds erect, with free tips erect, 0.5–2 mm; floral tube slightly curved upward to± straight, 15–40 mm; sepals 6–13 mm; petals yellow, broadly elliptic to rhombic-ovate, 5–16 mm; filaments 4–18 mm, anthers 2–3.5 mm, pollen ca. 50% fertile; style 20–40 mm, stigma surrounded by anthers at anthesis. |
Capsules | ellipsoid-rhombic to subglobose, 4-angled, 4–6(–10) × 1.5–3 mm, stipe 0–4 mm, valve midrib raised at distal end, indehiscent or tardily dehiscent distally; sessile. |
narrowly lanceoloid, 10–20 ×2–3 mm. |
Seeds | clustered in each locule, ovoid, surface minutely papillose, 1 × 0.5 mm. |
brown, sometimes flecked with dark red spots, ellipsoid, 1–1.9 × 0.4–0.8 mm. |
2n | = 14. |
= 14. |
Oenothera linifolia |
Oenothera clelandii |
|
Phenology | Flowering Apr–Jun(–Aug). | Flowering Jun–Aug(–Sep). |
Habitat | Prairies, open woodlands, open rocky and sandy sites, roadsides. | Fields, prairies, sandy soil. |
Elevation | 0–400 m. (0–1300 ft.) | 150–300 m. (500–1000 ft.) |
Distribution |
AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; TX
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AR; IA; IL; IN; KY; MI; MN; MO; NJ; NY; VA; WI; ON
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Discussion | Kneiffia linearifolia Spach (1835) is an illegitimate name based on Oenothera linifolia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera clelandii is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous (W. Dietrich and W. L. Wagner 1988). Some localities in the easternmost states may represent introductions, primarily occurring in disturbed areas along roads and railroad lines. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Peniophyllum | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Candela |
Sibling taxa | ||
Synonyms | Kneiffia linifolia, O. linifolia var. glandulosa, Peniophyllum linifolium | |
Name authority | Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821) | W. Dietrich, P. H. Raven & W. L. Wagner: Ann. Missouri Bot. Gard. 70: 196. (1983) |
Web links |