Oenothera organensis |
Oenothera psammophila |
|
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Organ Mountain evening primrose |
St. Anthony dunes evening primrose |
|
Habit | Herbs perennial, moderately hirsute (hairs often with reddish purple, pustulate bases), alsostrigillose and becoming glandular puberulent distally; initially from slender taproot with single rosette, later developing numerous adventitious shoots from taproot and lateral roots, root system then appearing fibrous. | Herbs perennial, caulescent, glabrous, also with resinous exudate, especially on younger leaves; from woody taproot. |
Stems | weakly erect to ascending, many from base, forming clumps 1–1.5 m diam., often branched distally, 30–60 cm. |
decumbent, usually branched, 10–30 cm, becoming woody and buried in sand. |
Leaves | in a weakly developed basal rosette and cauline, basal 9–23 × 1–2.5 cm, cauline 5–11 × 1.5–3.5 cm; petiole 0.5–1.5 cm; blade very narrowly oblanceolate to narrowly elliptic, margins undulate, remotely and bluntly 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 | opening near sunset, not strongly scented; buds with free tips terminal, erect, 3–10 mm; floral tube straight, 100–165(–190) mm; sepals 25–50 mm; petals yellow, fading deep reddish orange, broadly obovate with truncate apex, or obcordate, 30–55 mm; filaments 18–35 mm, anthers 10–19 mm; style 140–235 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 to slightly spreading at acute angle from stem, cylindrical, 25–35 ×4–5.5 mm, dehiscent at least 3/4 their length. |
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 | numerous, in 2 distinct rows per locule, dark reddish brown, sometimes with darker flecks, obovoid, asymmetrical, irregularly angled, 1.5–2.1 × 1–1.2 mm, surface irregularly pitted and with collapsed papillae. |
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 | = 14. |
= 14. |
Oenothera organensis |
Oenothera psammophila |
|
Phenology | Flowering Jun–Sep. | Flowering May–Jul. |
Habitat | In larger rhyolite canyons, along water courses, in eroded basins filled with gravel and rocks. | On barren areas of drifting sand at interface between outcrops of lava and sand dunes. |
Elevation | 1800–2300 m. (5900–7500 ft.) | 1500–1700 m. (4900–5600 ft.) |
Distribution |
NM |
ID |
Discussion | Oenothera organensis is known only from the Organ Mountains, Doña Ana County, especially on the east side. Various studies have been done to assess the status of this narrow endemic and estimate 2000 to 5000 individuals with wide fluctuations likely due to variation in rainfall (W. Dietrich et al. 1985). Oenothera organensis could decline if degradation of habitat increases in the Organ Mountains. The genetics and population biology of this taxon have been heavily studied in the past (summarized in Dietrich et al.). It is self-incompatible. (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 | O. macrosiphon | Pachylophus psammophilusa., O. cespitosa var. psammophila |
Name authority | Munz ex S. Emerson: Genetics 23: 190. (1938) | (A. Nelson & J. F. Macbride) W. L. Wagner, Stockhouse & W. M. Klein: Monogr. Syst. Bot. Missouri Bot. Gard. 12: 84. (1985) |
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