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Curtiss' evening primrose

shale barren evening primrose

Habit Herbs biennial or short-lived perennial, densely to sparsely strigillose, sometimes also sparsely glandular puberulent distally. 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.
Stems

sometimes with lateral branches arisingobliquely from rosette, 30–80 cm.

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

Leaves

in a basal rosette and cauline, basal 7–17 × 0.5–1.5 cm, cauline 2–8 × 0.5–1.5 cm;

blade narrowly oblanceolate, gradually narrowly elliptic to narrowly oblong distally, margins lobed to remotely dentate or subentire;

bracts slightly longer than capsule they subtend.

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.

Inflorescences

open, lax, without lateral branches, mature buds usually not overtopping spike apex.

curved with ascending tip, unbranched.

Flowers

1 or 2 per spike opening per day near sunset;

buds erect, with free tips erect to spreading, 0.3–0.8 mm;

floral tube slightly curved upward to straight, 23–37 mm;

sepals 7–13 mm;

petals yellow, broadly elliptic to rhombic-ovate, 8–17 mm;

filaments 6–10 mm, anthers 1.5–4 mm, pollen ca. 50% fertile;

style 30–45 mm, stigma surrounded by anthers at anthesis.

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.

Capsules

narrowly lanceoloid, 10–25 ×2–3 mm.

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.

Seeds

brown, sometimes flecked with darkred spots, ellipsoid, 1–1.3 × 0.5–0.7 mm.

1.3–1.9 × 0.7–1.1 mm.

2n

= 14.

= 14.

Oenothera curtissii

Oenothera argillicola

Phenology Flowering Jun–Sep. Flowering (Jun–)Jul–Oct.
Habitat Dry places, pine-oak woods, fields, roadsides, sandy soil. Open sites on Devonian Brallier shale slopes, barrens, outcrops or adjacent roadsides in mid-Appalachian Allegheny Mountains.
Elevation 0–60 m. (0–200 ft.) 150–700 m. (500–2300 ft.)
Distribution
from FNA
AL; FL; GA; SC
[BONAP county map]
from FNA
MD; PA; VA; WV
[BONAP county map]
Discussion

Oenothera curtissii is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous (W. Dietrich and W. L. Wagner 1988). It is known only from northern Florida, adjacent southern Georgia and southeastern Alabama, and one disjunct locality in South Carolina (Allendale County).

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

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.)

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Candela Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Oenothera
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. 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. 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
Synonyms O. heterophylla var. curtissii O. argillicola var. pubescens
Name authority Small: Fl. S.E. U.S. ed. 2, 1353. (1913) Mackenzie: Torreya 4: 56. (1904)
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