Oenothera humifusa |
Oenothera brachycarpa |
|
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seabeach evening-primrose |
shortfruit evening-primrose |
|
Habit | Herbs annual or short-lived perennial, densely strigillose, sometimes also villous, also becoming glandular puberulent distally. | Herbs acaulescent or sometimes caulescent, strigillose, also hirsute, hairs often with reddish purple pustulate base, glandular puberulent distally; from a woody taproot, sometimes lateral roots producing adventitious shoots. |
Stems | erect to decumbent, much branched, 10–50(–90) cm. |
(when present) ascending, longer ones becoming decumbent, usually densely leafy, 0–20(–36) 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, sometimes also cauline, (3.1–)5–21(–34) × (0.3–)1.5–3.5(–5.3) cm; petiole (0.8–)2.5–11(–15) cm; blade usually lanceolate to elliptic, rhombic-obovate, sometimes suborbicular or linear, usually irregularly pinnatifid, some sinuses extending nearly to midrib, usually with a large terminal lobe (0.1–)1.5–2(–2.4) cm, margins erose, apex acute to obtuse or rounded. |
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. |
usually 1–3, rarely more, opening per day near sunset, weakly scented; buds with unequal free tips 1–7 mm; floral tube (90–)120–210(–220) mm; sepals 38–55 mm; petals pale yellow to yellow, fading pale orange to pink, drying lavender to purple, usually broadly rhombic-obovate, sometimes obovate, (38–)45–58(–62) mm, distal margin usually erose; filaments (16–)20–32 mm, anthers (8–)13–21 mm; style (123–)155–240(–255) mm, stigma exserted beyond anthers at anthesis. |
Capsules | cylindrical, sometimes slightly enlarged toward apex, 15–45 × 2–3 mm. |
leathery or corky, ovoid to narrowly ellipsoid, ± winged, wings 0–3(–5) mm wide, sometimes capsule with corky thickening between wings, then capsule only 4-angled, body (12–)18–40 × 6–10 mm, dehiscent 1/4 their length; pedicel 0–3 mm. |
Seeds | usually ellipsoid to broadly ellipsoid, rarely subglobose, 1–2 × 0.5–0.9 mm. |
usually numerous, in 1 or 2 rows per locule, obovoid to subcuboid, 3–5 × 1.8–2.2 mm. |
2n | = 14. |
= 14. |
Oenothera humifusa |
Oenothera brachycarpa |
|
Phenology | Flowering Apr–Nov. | Flowering Mar–Aug. |
Habitat | Dunes, open sandy places along or near Atlantic coast. | Rocky sites, usually on limestone, shale, or gypsum, on igneous substrates from canyons and slopes in Chihuahuan Desert scrub, grasslands, oak-pine-juniper woodlands, open sites in ponderosa pine-Douglas fir forests. |
Elevation | 0–10 m. (0–0 ft.) | 1000–2700 m. (3300–8900 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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AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, Sonora)
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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.) |
Oenotherabrachycarpa occurs from southeastern Arizona in southern Navajo, southeastern Pima, Graham, Santa Cruz, and Cochise counties, east across southern New Mexico to Val Verde and Pecos counties in trans-Pecos Texas. (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. Megapterium |
Sibling taxa | ||
Synonyms | O. niveifolia, O. sinuata var. humifusa, Raimannia humifusa | Lavauxia brachycarpa, L. graminifolia, L. wrightii, Megapterium brachycarpum, M. brachycarpum var. wrightii, O. australis, O. brachycarpa var. wrightii, O. cespitosa subsp. australis, O. cespitosa var. australis, O. graminifolia, O. wrightii, Pachylophus australis |
Name authority | Nuttall: Gen. N. Amer. Pl. 1: 245. (1818) | A. Gray: Smithsonian Contr. Knowl. 3(5): 70. (1852) |
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