Oenothera psammophila |
Oenothera mexicana |
|
---|---|---|
St. Anthony dunes evening primrose |
Mexican evening primrose |
|
Habit | Herbs perennial, caulescent, glabrous, also with resinous exudate, especially on younger leaves; from woody taproot. | Herbs annual, moderately to sparsely strigillose and densely long-villous, sometimes also becoming glandular puberulent distally. |
Stems | decumbent, usually branched, 10–30 cm, becoming woody and buried in sand. |
erect to ascending, usually unbranched, or with arcuate lateral branches arising from rosette, 15–40(–60) 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. |
in a basal rosette and cauline, basal 6–10 × 1–2.5 cm, cauline 3–7.5 × 0.8–2 cm; blade usually grayish green, narrowly oblanceolate to narrowly oblanceolate, margins deeply lobed, lobes usually dentate; bracts distalmost erect, revolute. |
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. |
usually 1 opening per day near sunset; buds erect, with free tips erect or appressed, 0.5–2.5 mm; floral tube 23–28 mm; sepals 5–12 mm; petals yellow, fading orange, broadly obovate or shallowly obcordate, 6–15 mm; filaments 4–12 mm, anthers 3–4 mm, pollen 85–100% fertile; style 27–40 mm, stigma surrounded by 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. |
cylindrical, sometimes slightly enlarged toward apex, 25–45 × 2.5–3 mm. |
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. |
ellipsoid to subglobose, 0.8–1.2 × 0.3–0.5 mm. |
2n | = 14. |
= 14. |
Oenothera psammophila |
Oenothera mexicana |
|
Phenology | Flowering May–Jul. | Flowering Apr–May. |
Habitat | On barren areas of drifting sand at interface between outcrops of lava and sand dunes. | Open, sandy sites. |
Elevation | 1500–1700 m. (4900–5600 ft.) | 30–200 m. (100–700 ft.) |
Distribution |
ID |
TX |
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 mexicana is known only from southeastern Texas (Atascosa, Aransas, Bexar, Brooks, Burleson, De Witt, Frio, Gonzales, Kenedy, Medina, Newton, Refugio, San Patricio, Waller, and Washington counties). It is self-compatible and autogamous, but not a PTH species. (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 | O. laciniata var. mexicana, O. sinuata var. hirsuta, Raimannia mexicana |
Name authority | (A. Nelson & J. F. Macbride) W. L. Wagner, Stockhouse & W. M. Klein: Monogr. Syst. Bot. Missouri Bot. Gard. 12: 84. (1985) | Spach: Nouv. Ann. Mus. Hist. Nat. 4: 347. (1836) |
Web links |