Oenothera podocarpa |
Oenothera riparia |
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Habit | Herbs annual, villous proximally, glabrate, strigillose and/or glandular puberulent distally, leaves glabrate to densely villous, glabrate in age; from stout taproot. | Herbs perennial, sparsely strigillose, becoming glabrate distally, usually also glandular puberulent distally; from a somewhat fleshy rootstock, forming adventitious roots where submerged. |
Stems | ascending to erect, unbranched or well-branched at base and distally, 15–100 cm. |
erect or ascending, usually many-branched throughout, proximal branches often somewhat spongy, 50–120 cm. |
Leaves | in a basal rosette and cauline, basal 3–15 × 0.5–1 cm, blade lyrate; cauline 1–9 × 0.1–0.8 cm, blade linear to very narrowly elliptic or narrowly lanceolate, margins sinuate-dentate to subentire. |
in a basal rosette and cauline, softly succulent, 4–13.5 × 0.8–2.1 cm, petiole 0–1.5 cm, blade lanceolate to elliptic-lanceolate, margins remotely denticulate. |
Inflorescences | erect, flowers in axils of distalmost few nodes. |
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Flowers | 4-merous, zygomorphic, opening at sunset; floral tube 6–10 mm; sepals 6–12 mm; petals white, fading pink to red, narrowly obovate, 5.5–9.5 mm, short-clawed; filaments 4–6 mm, anthers 2–3 mm, pollen 90–100% fertile; style 11–19 mm, stigma surrounded by anthers at anthesis. |
opening near sunrise; buds with free tips 0.5–2(–5) mm, erect to spreading; floral tube 14–20 mm; sepals 20–30 mm; petals bright yellow, fading pale pink or lavender, 16–27 mm; filaments 10–15 mm, anthers 7–8 mm, pollen 85–100% fertile; style 15–30 mm, stigma exserted beyond anthers at anthesis. |
Capsules | ellipsoid or narrowly obovoid, narrowly 4-winged, furrowed between wings, 6–8 × 2–3 mm, narrowed at base, stipe 0 mm; sessile. |
oblong-clavate to oblong-ellipsoid, 4-angled or 4-winged, and wings 0.1–0.2 mm, 7–15 × 4–6 mm, stipe 2–5 mm; sessile. |
Seeds | 4, yellowish to reddish brown, 2–3 × 1–1.5 mm. |
0.8 × 0.4 mm. |
2n | = 14. |
= 56. |
Oenothera podocarpa |
Oenothera riparia |
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Phenology | Flowering (May–)Jun–Oct. | Flowering May–Jul. |
Habitat | Disturbed sites, sandy washes, slopes, grasslands, meadows, pinyon-juniper or ponderosa pine woodlands, on volcanic cinders. | Isolated colonies in or at edge of water in marshes or slow-running rivers, apparently with at least some tidal influence. |
Elevation | 700–2800 m. (2300–9200 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AZ; NM; Mexico (Chihuahua, Durango, Sonora) |
GA; NC; SC; VA |
Discussion | Oenothera podocarpa occurs in Arizona from eastern Mohave County south through the mountains of central Arizona to eastern Pima County and the southwestern quarter of New Mexico, and in Mexico southward in the Sierra Madre Occidental to eastern Sonora and throughout the western halves of Chihuahua and Durango. P. H. Raven and D. P. Gregory (1972[1973]) determined O. podocarpa to be self-compatible and primarily autogamous. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera riparia has not been accepted as a distinct species for a long time. The conservative approach used by G. B. Straley (1977) is here followed in recognizing a broadly delimited O. fruticosa, except that the very distinctive coastal tidal-freshwater semi-aquatic octoploid populations (Straley 1982) are recognized as O. riparia. Plants of these coastal populations, which occur from southern Virginia to North Carolina, are more robust, more branched, and less pubescent than those of the two subspecies of O. fruticosa, and have slightly succulent leaves and more prominent adventitious roots (Straley 1982; D. Boufford, pers. comm.). Further field studies and cytological analyses are needed to fully understand the geographical and ecological limits of O. riparia and confirm that it is strictly an octoploid species. K. N. Krakos et al. (2014) determined that Oenothera riparia is self-incompatible and is pollinated by bees (Bombus, Lassioglossum, Megachile, Parallelia, Xylocopa, and Zale). (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. Gaura > subsect. Gaura | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Kneiffia |
Sibling taxa | ||
Synonyms | Gaura podocarpa, G. brassicacea, G. glandulosa, G. gracilis, G. hexandra subsp. gracilis, G. strigillosa, O. hexandra subsp. gracilis | Kneiffia riparia, O. tetragona var. riparia |
Name authority | (Wooton & Standley) Krakos & W. L. Wagner: PhytoKeys 28: 68. (2013) | Nuttall: Gen. N. Amer. Pl. 1: 247. (1818) |
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