Oenothera platanorum |
Oenothera argillicola |
|
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Fort Huachuca evening primrose |
shale barren evening primrose |
|
Habit | Herbs perennial, caulescent, strigillose, often densely so; from slender 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 | 1–several, ascending, 5–60 cm. |
erect to ascending, green or red, unbranched or with branches obliquely arising from rosette or in distal 1/2 of main stem. |
Leaves | in a basal rosette and cauline, basal 2–7 × 0.3–1.4 cm, blade narrowly elliptic to narrowly ovate, margins weakly serrulate to sinuate-pinnatifid; cauline 1.2–6 × 0.3–1 cm, blade narrowly elliptic to elliptic or ovate, proximal ones sinuate-pinnatifid, margins subentire or weakly serrulate. |
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 | erect. |
curved with ascending tip, unbranched. |
Flowers | 1–3 opening per day near sunrise; buds with free tips 0–0.1 mm; floral tube 9–14 mm; sepals 7.5–13 mm; petals rose purple, fading darker, 8–15 mm; filaments 4–9 mm, anthers 2.5–4 mm, pollen 85–100% fertile; style 12–19 mm, stigma surrounded by 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 | clavate or narrowly obovoid, 9–14 × 3–4 mm, apex attenuate to a sterile beak, valve midrib prominent in distal part, proximal stipe 4–15 mm, gradually tapering to base; 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 | narrowly obovoid, 0.7–0.9 × 0.3–0.5 mm. |
1.3–1.9 × 0.7–1.1 mm. |
2n | = 14. |
= 14. |
Oenothera platanorum |
Oenothera argillicola |
|
Phenology | Flowering Mar–Aug. | Flowering (Jun–)Jul–Oct. |
Habitat | Streambeds and near springs. | Open sites on Devonian Brallier shale slopes, barrens, outcrops or adjacent roadsides in mid-Appalachian Allegheny Mountains. |
Elevation | 700–1900 m. (2300–6200 ft.) | 150–700 m. (500–2300 ft.) |
Distribution |
AZ; Mexico (Sonora) |
MD; PA; VA; WV |
Discussion | Oenothera platanorum is known only from the southeastern counties of Cochise, Pinal, and Santa Cruz in Arizona. It was recently collected in Sonora, Mexico. The species is very similar to both O. texensis, from which it differs in its smaller flowers, and the widespread O. rosea, from which it differs in the somewhat larger flowers and in forming seven bivalents in meiosis and fully fertile pollen, whereas O. rosea is a PTH species. (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 | O. argillicola var. pubescens | |
Name authority | P. H. Raven & D. R. Parnell: Madroño 20: 246. (1970) | Mackenzie: Torreya 4: 56. (1904) |
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