Oenothera hispida |
Oenothera psammophila |
|
---|---|---|
|
St. Anthony dunes evening primrose |
|
Habit | Herbs perennial, spreading by rhizomes (forming colonies), strigillose, often also villous; from taproot. | Herbs perennial, caulescent, glabrous, also with resinous exudate, especially on younger leaves; from woody taproot. |
Stems | ascending to decumbent, several-branched from base, usually also irregularly branched distally, sometimes with a single, unbranched stem, 20–60(–120) cm. |
decumbent, usually branched, 10–30 cm, becoming woody and buried in sand. |
Leaves | in a basal rosette and cauline, 0.5–7.5(–9.5) × 0.1–2.2 cm, blade narrowly lanceolate to elliptic, margins subentire or shallowly sinuate-dentate. |
(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. |
Flowers | 4-merous, zygomorphic, opening near sunset; floral tube 4–14 mm; sepals 7–11(–14) mm; petals white, fading red, slightly unequal, elliptic, 6–10 mm, clawed; filaments 4–8.5 mm, anthers 3–6 mm, pollen 90–100% fertile; style 12–26 mm, stigma exserted beyond anthers at anthesis. |
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. |
Capsules | erect, pyramidal in distal 1/2, conspicuously bulging at base of distal pyramidal part, strongly 4-angled, conspicuously bulging at base, abruptly constricted to terete proximal part, 7–13 × 3–5 mm; sessile. |
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. |
Seeds | (2 or)3 or 4(–8), reddish brown, 2–2.5 × 1–1.3 mm. |
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. |
2n | = 28. |
= 14. |
Oenothera hispida |
Oenothera psammophila |
|
Phenology | Flowering May–Jul(–Nov). | Flowering May–Jul. |
Habitat | Sandy loam. | On barren areas of drifting sand at interface between outcrops of lava and sand dunes. |
Elevation | 60–1900 m. (200–6200 ft.) | 1500–1700 m. (4900–5600 ft.) |
Distribution |
AR; CA; GA; TX; c Mexico |
ID |
Discussion | Oenothera hispida is native across the eastern half of Texas, south through Mexico to Oaxaca and Puebla; it is naturalized in Sevier County, Arkansas, coastal southern California, and Glynn County Georgia. P. H. Raven and D. P. Gregory (1972[1973]) reported Oenothera hispida to be self-incompatible. It occasionally forms hybrids with O. suffrutescens. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Gaura hispida, G. crispa, G. drummondii, G. roemeriana, O. xenogaura, Schizocarya crispa, S. drummondii | Pachylophus psammophilusa., O. cespitosa var. psammophila |
Name authority | (Bentham) W. L. Wagner, Hoch & Zarucchi: PhytoKeys 50: 26. (2015) | (A. Nelson & J. F. Macbride) W. L. Wagner, Stockhouse & W. M. Klein: Monogr. Syst. Bot. Missouri Bot. Gard. 12: 84. (1985) |
Web links |