Oenothera xylocarpa |
Oenothera argillicola |
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wood fruit evening primrose, woodyfruit evening primrose |
shale barren evening primrose |
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Habit | Herbs perennial, acaulescent, densely short-hirsute, also sometimes sparsely long-hirsute distally; from a thick, fleshy taproot. | Herbs biennial or short-lived perennial, strigillose and sparsely to moderately villous, hairs sometimes pustulate, pustules with green or red bases, inflorescence glabrous or sparsely glandular puberulent, sometimes also sparsely villous. |
Stems | erect to ascending, green or red, unbranched or with branches obliquely arising from rosette or in distal 1/2 of main stem. |
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Leaves | in a basal rosette, 2.6–4.2(–6.2) × 1.4–4.2 cm; petiole 2.5–9(–11.5) cm; blade usually oblanceolate to obovate, sometimes suborbiculate, margins dentate, pinnately lobed, lateral lobes oblong to lanceolate, often absent or reduced to only a few lobes toward terminal lobe, base rounded to cordate. |
in a basal rosette and cauline, basal 7–25 × 0.7–2 cm, cauline 6–13 × 0.4–1 cm; blade dark green, somewhat glossy, very narrowly oblanceolate to narrowly oblanceolate, linear-elliptic, lanceolate, or nearly linear, margins flat, entire or remotely and bluntly dentate, sometimes with larger teeth near base; bracts persistent. |
Inflorescences | curved with ascending tip, unbranched. |
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Flowers | usually 1–3, rarely more, opening per day near sunset; buds erect, quadrangular, without free tips; floral tube 27–45(–55) mm; sepals 25–30 mm; petals intensely yellow, fading deep salmon red, obcordate, 25–38 mm; filaments 17–23 mm, anthers 7–10 mm; style 44–65(–80) mm, stigma somewhat exserted beyond anthers at anthesis. |
opening near sunset; buds erect, 4–8 mm diam., with free tips subterminal, divergent and hornlike, 3–9 mm; floral tube 32–52 mm; sepals yellowish green to yellow, sometimes flushed with red, especially at apex, 27–38 mm; petals yellow to pale yellow, fading pale yellow to pale yellowish orange, very broadly obcordate or obovate, 25–42 mm; filaments 20–27 mm, anthers 9–13 mm, pollen 90–100% fertile; style 60–85 mm, stigma exserted beyond anthers at anthesis. |
Capsules | moderately thin and flexible, lanceoloid, falcate or sigmoid, often contorted and twisted, 4-angled, 35–90 × 7–11 mm, gradually tapering to a long, slender, sterile apex, 10–30(–40) mm, valves conspicuously wrinkled, dehiscent 2/3–3/4 their length; sessile. |
spreading at nearly a right angle to stem, curved upward, sometimes secund, dull green or rusty brown when dry, narrowly lanceoloid to lanceoloid, 20–40 × 4–6 mm, free tips of valves 1–2 mm. |
Seeds | numerous, in 1 row per locule, often forming 2 rows near base of capsule, obovoid, 2.4–3.2 × 1.3–1.7 mm, surface coarsely rugose. |
1.3–1.9 × 0.7–1.1 mm. |
2n | = 14. |
= 14. |
Oenothera xylocarpa |
Oenothera argillicola |
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Phenology | Flowering Jun–Jul(–Aug). | Flowering (Jun–)Jul–Oct. |
Habitat | Open meadows, flats or slopes on loose granitic gravel, sand, or pumice in Pinus jeffreyi forests with Artemisia tridentata, or in Pinus contorta subsp. murrayana and Abies magnifica forests. | Open sites on Devonian Brallier shale slopes, barrens, outcrops or adjacent roadsides in mid-Appalachian Allegheny Mountains. |
Elevation | 2200–3100 m. (7200–10200 ft.) | 150–700 m. (500–2300 ft.) |
Distribution |
CA; NV |
MD; PA; VA; WV |
Discussion | Oenothera xylocarpa is known from three disjunct areas in California and adjacent Nevada: Mount Rose, Washoe County, Nevada; southern Sierra Nevada, southwestern Mono County, California, from the vicinity of Crestview south to Casa Diablo; and the area in the southern Sierra Nevada bounded by Horseshoe and Big Whitney meadows to the east and north, and Casa Vieja and Volcano Meadows to the south and west, west-central Inyo and eastern Tulare counties, California. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera argillicola is one of eight angiosperm species restricted to the Devonian Brallier shale barrens, but among them only O. argillicola and Trifolium virginicum occur throughout the shale barren region. Oenothera argillicola has plastome V and a CC genome composition. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Anogra xylocarpa | O. argillicola var. pubescens |
Name authority | Coville: Contr. U.S. Natl. Herb. 4: 105, plate 8. (1893) | Mackenzie: Torreya 4: 56. (1904) |
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