Oenothera psammophila |
Oenothera humifusa |
|
---|---|---|
St. Anthony dunes evening primrose |
seabeach evening-primrose |
|
Habit | Herbs perennial, caulescent, glabrous, also with resinous exudate, especially on younger leaves; from woody taproot. | Herbs annual or short-lived perennial, densely strigillose, sometimes also villous, also becoming glandular puberulent distally. |
Stems | decumbent, usually branched, 10–30 cm, becoming woody and buried in sand. |
erect to decumbent, much branched, 10–50(–90) cm. |
Leaves | (6–)8–9(–14.2) × (0.7–)1.5–2(–3.1) cm; petiole 3–9 cm; blade narrowly oblanceolate to oblanceolate, margins usually subentire or repand or remotely dentate, rarely serrate, apex acute. |
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. |
Flowers | 1–3 per stem opening per day near sunset, with sweet scent; buds erect; floral tube 42–60 mm; sepals 22–28 mm; petals white, fading rose pink to rose, 23–40 mm; filaments 17–19 mm, anthers 13–16 mm; style 60–72(–88) mm, stigma exserted beyond anthers at anthesis. |
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. |
Capsules | somewhat curved and often somewhat twisted, lanceoloid-cylindrical, nearly cylindrical, (20–)30–47 × 7–8 mm, gradually tapering to apex, 6–8 mm, dehiscent nearly throughout their length, valve margins with a conspicuous, irregular, wavy ridge; pedicel 1–5 mm. |
cylindrical, sometimes slightly enlarged toward apex, 15–45 × 2–3 mm. |
Seeds | numerous, in 2 distinct rows per locule, narrowly obovoid, 2.5–3 × 1.2–1.4 mm, embryo 7/8 of seed volume, surface finely reticulate; seed collar with a broad membrane sealing cavity, margin entire. |
usually ellipsoid to broadly ellipsoid, rarely subglobose, 1–2 × 0.5–0.9 mm. |
2n | = 14. |
= 14. |
Oenothera psammophila |
Oenothera humifusa |
|
Phenology | Flowering May–Jul. | Flowering Apr–Nov. |
Habitat | On barren areas of drifting sand at interface between outcrops of lava and sand dunes. | Dunes, open sandy places along or near Atlantic coast. |
Elevation | 1500–1700 m. (4900–5600 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
ID |
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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Discussion | Oenothera psammophila is known only from the dune area north and west of St. Anthony, Fremont County. It is unique in Oenothera because of the exudate produced on the leaves to which sand particles adhere, forming a sand sheath, presumably for protection from the constantly blowing sand particles. It is self-incompatible (W. L. Wagner et al. 1985; Wagner 2005). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Pachylophus psammophilusa., O. cespitosa var. psammophila | O. niveifolia, O. sinuata var. humifusa, Raimannia humifusa |
Name authority | (A. Nelson & J. F. Macbride) W. L. Wagner, Stockhouse & W. M. Klein: Monogr. Syst. Bot. Missouri Bot. Gard. 12: 84. (1985) | Nuttall: Gen. N. Amer. Pl. 1: 245. (1818) |
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