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shale barren evening primrose

Mexican evening primrose, pinkladies, showy evening primrose

Habit Herbs biennial or short-lived perennial, strigillose and sparsely to moderately villous, hairs sometimes pustulate, pustules with green or red bases, inflorescence glabrous or sparsely glandular puberulent, sometimes also sparsely villous. Herbs perennial, caulescent, glabrate to strigillose, usually also sparsely hirsute; from slender taproot and spreading by rhizomes.
Stems

erect to ascending, green or red, unbranched or with branches obliquely arising from rosette or in distal 1/2 of main stem.

many, erect, 4–60 cm.

Leaves

in a basal rosette and cauline, basal 7–25 × 0.7–2 cm, cauline 6–13 × 0.4–1 cm;

blade dark green, somewhat glossy, very narrowly oblanceolate to narrowly oblanceolate, linear-elliptic, lanceolate, or nearly linear, margins flat, entire or remotely and bluntly dentate, sometimes with larger teeth near base;

bracts persistent.

in a basal rosette and cauline, basal 2–9 × 0.3–3.2 cm, blade oblanceolate to obovate, margins subentire or sinuate-pinnatifid;

cauline 1–10 × 0.3–3.5 cm, blade narrowly elliptic to ovate, margins subentire or serrulate to sinuate-pinnatifid.

Inflorescences

curved with ascending tip, unbranched.

sharply nodding.

Flowers

opening near sunset;

buds erect, 4–8 mm diam., with free tips subterminal, divergent and hornlike, 3–9 mm;

floral tube 32–52 mm;

sepals yellowish green to yellow, sometimes flushed with red, especially at apex, 27–38 mm;

petals yellow to pale yellow, fading pale yellow to pale yellowish orange, very broadly obcordate or obovate, 25–42 mm;

filaments 20–27 mm, anthers 9–13 mm, pollen 90–100% fertile;

style 60–85 mm, stigma exserted beyond anthers at anthesis.

1–3 opening per day near sunrise in some populations, near sunset in others;

buds with free tips 0–4 mm;

floral tube 12–25 mm;

sepals 15–50 mm;

petals pink to rose, fading darker, or white, fading pink, 15–45 mm;

filaments 10–22 mm, anthers 6–16 mm, pollen 85–100% fertile;

style 20–55 mm, stigma exserted beyond anthers at anthesis.

Capsules

spreading at nearly a right angle to stem, curved upward, sometimes secund, dull green or rusty brown when dry, narrowly lanceoloid to lanceoloid, 20–40 × 4–6 mm, free tips of valves 1–2 mm.

narrowly obovoid to narrowly rhombic-ellipsoid, angled, 10–25 × 3.5–6 mm, apex attenuate to a sterile beak, valve midrib prominent, proximal stipe cylindrical, not tapering to base, (4–)8–15 mm;

sessile.

Seeds

1.3–1.9 × 0.7–1.1 mm.

narrowly obovoid, 1–1.2 × 0.5–0.6 mm.

2n

= 14.

= 14, 28, 42.

Oenothera argillicola

Oenothera speciosa

Phenology Flowering (Jun–)Jul–Oct. Flowering (Feb–)Apr–Jul(–Oct).
Habitat Open sites on Devonian Brallier shale slopes, barrens, outcrops or adjacent roadsides in mid-Appalachian Allegheny Mountains. Grasslands, glades, open woodlands, disturbed places, pastures, rail­roads, roadsides, loamy or sandy soil, sometimes clay.
Elevation 150–700 m. (500–2300 ft.) 10–900 m. (0–3000 ft.)
Distribution
from FNA
MD; PA; VA; WV
[BONAP county map]
from FNA
AR; IA; IL; IN; KS; LA; MO; NE; NM; OK; TX; Mexico (Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí, Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
Discussion

Oenothera argillicola is one of eight angiosperm species restricted to the Devonian Brallier shale barrens, but among them only O. argillicola and Trifolium virginicum occur throughout the shale barren region. Oenothera argillicola has plastome V and a CC genome composition.

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

Oenothera speciosa is widely cultivated worldwide for its showy flowers and easy maintenance. It is not known to be definitely naturalized, but tends to persist or become adventive due to its aggressive vegetative reproduction.

(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. Oenothera Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Hartmannia
Sibling taxa
O. acutissima, O. albicaulis, 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. 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
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. 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. 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. argillicola var. pubescens Hartmannia berlandieri, H. reverchonii, O. berlandieri, O. delessertiana, O. hirsuta, O. obtusifolia, O. shimekii, O. spachii, O. speciosa var. berlandieri, O. speciosa var. childsii, O. tetraptera var. childsii, Xylopleurum berlandieri, X. drummondii, X. hirsutum, X. obtusifolium, X. speciosum
Name authority Mackenzie: Torreya 4: 56. (1904) Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 119. (1821)
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