Oenothera humifusa |
Oenothera gaura |
|
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seabeach evening-primrose |
biennial bee-blossom |
|
Habit | Herbs annual or short-lived perennial, densely strigillose, sometimes also villous, also becoming glandular puberulent distally. | Herbs usually robust winter-annual, sometimes biennial, usually moderately to densely villous, rarely short-hirtellous, also glandular puberulent; from fleshy taproot. |
Stems | erect to decumbent, much branched, 10–50(–90) cm. |
usually well-branched distal to base, 50–180 cm. |
Leaves | in a basal rosette and cauline, basal 4–8 × 0.7–1 cm, cauline 1–7 × 0.3–1.5 cm; blade usually grayish green, narrowly oblong to narrowly elliptic or narrowly obovate, margins remotely shallowly dentate to subentire; bracts spreading, flat. |
in a basal rosette and cauline, basal 8–20 × 1.5–3 cm, blade oblanceolate, margins irregularly toothed to lobed; cauline 1.5–12 × 0.5–3 cm, blade narrowly elliptic to elliptic or lanceolate, margins subentire or undulate-denticulate. |
Flowers | usually 1 opening per day near sunset; buds erect, with free tips erect and appressed or slightly spreading, 0.5–2 mm; floral tube 15–35 mm; sepals3–11 mm; petals yellow, very broadly obovate or obcordate, 4.5–16 mm; filaments 4–11 mm, anthers 2–5.5 mm, pollen ca. 50% fertile; style 23–45 mm, stigma surrounded by anthers at anthesis. |
4-merous, zygomorphic, opening at sunset; floral tube 6–13 mm; sepals 5–13 mm; petals white, fading pink to red, narrowly elliptic-obovate, 6–12 mm; filaments 5–10 mm, anthers 2–4 mm, pollen 35–65% fertile; style 12–15 mm, stigma surrounded by anthers. |
Capsules | cylindrical, sometimes slightly enlarged toward apex, 15–45 × 2–3 mm. |
ellipsoid, 4-angled, 5–9 × 2–3 mm; sessile. |
Seeds | usually ellipsoid to broadly ellipsoid, rarely subglobose, 1–2 × 0.5–0.9 mm. |
3–6, light to reddish brown, 2–2.5 × 1–1.3 mm. |
2n | = 14. |
= 14. |
Oenothera humifusa |
Oenothera gaura |
|
Phenology | Flowering Apr–Nov. | Flowering Jun–Oct. |
Habitat | Dunes, open sandy places along or near Atlantic coast. | Open woods, fields, along streams, disturbed sites, ditch banks, roadsides, railway embankments. |
Elevation | 0–10 m. (0–0 ft.) | 100–600 m. (300–2000 ft.) |
Distribution |
AL; DE; FL; GA; LA; MD; MS; NC; NJ; PA; SC; VA; Dunes; open sandy places along or near Atlantic coast; West Indies (Cuba); Bermuda
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CT; DC; DE; IA; IL; IN; KY; MA; MD; MI; MN; NC; NJ; NY; OH; PA; TN; VA; VT; WI; WV; ON; QC
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Discussion | Oenothera humifusa 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). The inland collection from Iredell County, North Carolina, presumably represents an introduction. There are two geographically separated morphological forms of O. humifusa. Plants of one form are somewhat decumbent, with subentire cauline leaves and bracts; this form occurs in the southern part of the range. The other form is more upright, with more deeply divided leaves; it occurs from North Carolina northward. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera gaura is a PTH species and forms a ring of 14 chromosomes in meiosis. It is self-compatible and autogamous (P. H. Raven and D. P. Gregory 1972[1973]), and may have been derived from O. filiformis. (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. Oenothera > subsect. Raimannia | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Gaura > subsect. Gaura |
Sibling taxa | ||
Synonyms | O. niveifolia, O. sinuata var. humifusa, Raimannia humifusa | Gaura biennis |
Name authority | Nuttall: Gen. N. Amer. Pl. 1: 245. (1818) | W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 212. (2007) |
Web links |