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Organ Mountain evening primrose

Mckelvey's beeblossom

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, clumped, long-villous, more sparsely so distally, hairs erect, 2–4 mm, also strigillose, sometimes glabrate distally or also sparsely glandular puberulent; from twisted, woody rootstock.
Stems

weakly erect to ascending, many from base, forming clumps 1–1.5 m diam., often branched distally, 30–60 cm.

ascending, branched below or just above ground, branched also proximal to inflorescences, 30–70(–120) cm.

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.

in a basal rosette and cauline, basal 3–17 × 0.8–2 cm, blade oblanceolate, cauline 1–6.5 × 0.1–1.5 cm, sessile, blade narrowly oblanceolate to elliptic, margins conspicuously sinuate-dentate, often undulate.

Inflorescences

slender.

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.

4-merous, zygomorphic, opening near sunset;

floral tube 2–3.5 mm;

sepals 6–12 mm;

petals white, fading dark pink to red, slightly unequal, elliptic-obovate, 7–11 mm, long-clawed;

stamens presented in lower 1/2 of flower, filaments 5–9 mm, lanate at very base, anthers 2–4 mm, pollen 90–100% fertile;

style 9–16 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.

reflexed, lanceoloid to narrowly ovoid, narrowly 4-winged, 8–19 × 1.5–2 mm, tapering to a sterile stipe 3–9 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.

(1 or)2–4, 2–3 × 1 mm, yellowish to reddish brown.

2n

= 14.

= 14.

Oenothera organensis

Oenothera mckelveyae

Phenology Flowering Jun–Sep. Flowering Mar–Jun.
Habitat In larger rhyolite canyons, along water courses, in eroded basins filled with gravel and rocks. Sandy soil.
Elevation 1800–2300 m. (5900–7500 ft.) 0–300 m. (0–1000 ft.)
Distribution
from FNA
NM
[BONAP county map]
from FNA
TX; Mexico (Nuevo León, Tamaulipas)
[BONAP county map]
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 mckelveyae, on the Rio Grande Plain, is found in an area bounded by from Dimmit and LaSalle counties east to Karnes and Refugio counties in the north, southward through south Texas, extending to northeastern Tamaulipas and adjacent Nuevo León. P. H. Raven and D. P. Gregory (1972[1973]) found Oenothera mckelveyae to be self-incompatible.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Emersonia Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Gaura > subsect. Stipogaura
Sibling taxa
O. acutissima, O. albicaulis, O. argillicola, O. arida, O. arizonica, O. biennis, O. boquillensis, O. brachycarpa, O. calcicola, O. californica, O. canescens, O. capillifolia, O. cavernae, O. cespitosa, O. cinerea, O. clelandii, O. coloradensis, O. cordata, O. coronopifolia, O. coryi, O. curtiflora, O. curtissii, O. deltoides, O. demareei, O. dodgeniana, O. drummondii, O. elata, O. engelmannii, O. falfurriae, O. filiformis, O. filipes, O. flava, O. fruticosa, O. gaura, O. gayleana, O. glaucifolia, O. glazioviana, O. grandiflora, O. grandis, O. harringtonii, O. hartwegii, O. havardii, O. heterophylla, O. hispida, O. howardii, O. humifusa, O. jamesii, O. kunthiana, O. laciniata, O. lavandulifolia, O. lindheimeri, O. linifolia, O. longissima, O. macrocarpa, O. mckelveyae, O. mexicana, O. nealleyi, O. neomexicana, O. nutans, O. nuttallii, O. oakesiana, O. pallida, O. parviflora, O. patriciae, O. perennis, O. pilosella, O. platanorum, O. podocarpa, O. primiveris, O. psammophila, O. pubescens, O. rhombipetala, O. riparia, O. rosea, O. serrulata, O. sessilis, O. simulans, O. sinuosa, O. spachiana, O. speciosa, O. stricta, O. suffrutescens, O. suffulta, O. tetraptera, O. texensis, O. toumeyi, O. triangulata, O. triloba, O. tubicula, O. villosa, O. wolfii, O. xylocarpa
O. acutissima, O. albicaulis, O. argillicola, O. arida, O. arizonica, O. biennis, O. boquillensis, O. brachycarpa, O. calcicola, O. californica, O. canescens, O. capillifolia, O. cavernae, O. cespitosa, O. cinerea, O. clelandii, O. coloradensis, O. cordata, O. coronopifolia, O. coryi, O. curtiflora, O. curtissii, O. deltoides, O. demareei, O. dodgeniana, O. drummondii, O. elata, O. engelmannii, O. falfurriae, O. filiformis, O. filipes, O. flava, O. fruticosa, O. gaura, O. gayleana, O. glaucifolia, O. glazioviana, O. grandiflora, O. grandis, O. harringtonii, O. hartwegii, O. havardii, O. heterophylla, O. hispida, O. howardii, O. humifusa, O. jamesii, O. kunthiana, O. laciniata, O. lavandulifolia, O. lindheimeri, O. linifolia, O. longissima, O. macrocarpa, O. mexicana, O. nealleyi, O. neomexicana, O. nutans, O. nuttallii, O. oakesiana, O. organensis, O. pallida, O. parviflora, O. patriciae, O. perennis, O. pilosella, O. platanorum, O. podocarpa, O. primiveris, O. psammophila, O. pubescens, O. rhombipetala, O. riparia, O. rosea, O. serrulata, O. sessilis, O. simulans, O. sinuosa, O. spachiana, O. speciosa, O. stricta, O. suffrutescens, O. suffulta, O. tetraptera, O. texensis, O. toumeyi, O. triangulata, O. triloba, O. tubicula, O. villosa, O. wolfii, O. xylocarpa
Synonyms O. macrosiphon Gaura villosa var. mckelveyae, Gaura mckelveyae
Name authority Munz ex S. Emerson: Genetics 23: 190. (1938) (Munz) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 213. (2007)
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