Oenothera psammophila |
Oenothera canescens |
|
---|---|---|
St. Anthony dunes evening primrose |
beakpod evening primrose, spotted evening-primrose |
|
Habit | Herbs perennial, caulescent, glabrous, also with resinous exudate, especially on younger leaves; from woody taproot. | Herbs low, forming clumps 10–50 cm diam., densely strigillose throughout; from a taproot, lateral roots producing adventitious shoots. |
Stems | decumbent, usually branched, 10–30 cm, becoming woody and buried in sand. |
many-branched from base, leafy, (10–)15–25(–38) cm. |
Leaves | (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. |
cauline, (0.3–)0.6–1.5(–2.5) × (0.05–)0.15–0.4(–0.6) cm, fascicles of small leaves 0.2–0.6 cm often present in non-flowering axils; petiole 0–0.1 cm; blade lanceolate to linear, base cuneate, apex acute. |
Flowers | 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. |
several opening per day near sunset; buds usually without free tips, rarely free tips 0.2–0.3 mm; sepals (7–)8–12 mm; petals pink, rarely white, streaked or flecked with red, fading bright purple, (8–)10–17 mm; filaments 6–8 mm, anthers often with red longitudinal stripe, 3–6 mm; style (16–)22–27 mm, stigma exserted beyond anthers at anthesis. |
Capsules | 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. |
woody, ovoid, narrowly winged, wings 0.8–1.5 mm wide, (7–)9–12(–14) × 2–4 mm (excluding wings), abruptly constricted to a conspicuous, sterile beak, (2–)3–4.5 mm, indehiscent; sessile. |
Seeds | 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. |
asymmetrically cuneiform or oblanceoloid, 1.2–1.5 × 0.4–0.5 mm. |
2n | = 14. |
= 14. |
Oenothera psammophila |
Oenothera canescens |
|
Phenology | Flowering May–Jul. | Flowering May–Aug. |
Habitat | On barren areas of drifting sand at interface between outcrops of lava and sand dunes. | Prairie depressions, playas, margins of ditches, temporary wet areas. |
Elevation | 1500–1700 m. (4900–5600 ft.) | (400–)700–1800 m. ((1300–)2300–5900 ft.) |
Distribution |
ID |
CO; KS; NE; NM; OK; TX; WY
|
Discussion | 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.) |
Oenothera canescens is restricted to prairie depressions, playas, ditch margins, and other places of temporary water in the High Plains of the western United States from Goshen County, Wyoming, southeast to Hayes County, Nebraska, south through eastern Colorado, the eastern tier of counties in New Mexico, western Kansas, and to Garza and Dawson counties in the Texas Panhandle; also disjunct populations from Chautauqua, Sedgwick, and Stafford counties, Kansas. The illegitimate names Gaurella guttulata (Geyer ex Hooker) Small, G. canescens (Torrey & Frémont) Cockerell, and Gauropsis guttulata (Geyer ex Hooker) Cockerell pertain here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Pachylophus psammophilusa., O. cespitosa var. psammophila | Gaurella canescens, Megapterium canescens, O. guttulata |
Name authority | (A. Nelson & J. F. Macbride) W. L. Wagner, Stockhouse & W. M. Klein: Monogr. Syst. Bot. Missouri Bot. Gard. 12: 84. (1985) | Torrey & Frémont in J. C. Fremont: Rep. Exped. Rocky Mts., 315. (1845) |
Web links |