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threadleaf evening-primrose, threadleaf sundrop

Habit Herbs annual, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot. Herbs biennial, villous and strigillose proximally, leaves glabrate or strigillose, also glandular puberulent distally, sometimes also sparsely villous; from stout, fleshy taproot.
Stems

unbranched or with many ascending branches arising near base, erect, 10–50 cm.

1 or few-branched from base, 50–120 cm.

Leaves

in a basal rosette and cauline, basal 1–2(–4) × 0.2–0.6 cm, petiole 0.2–1(–1.5) cm, blade ovate to obovate or narrowly elliptic;

cauline 1–4 × less than 0.1 cm, sessile, blade linear or filiform.

in a basal rosette and cauline, basal 6–20 × 1–3 cm, blade lanceolate to narrowly elliptic;

cauline 5–10 × 1–2.5 cm, blade lanceolate to narrowly elliptic, margins subentire or repand-denticulate.

Flowers

usually 1–3 opening per day near sunrise;

buds without free tips;

sepals 1.5–2 mm;

petals bright yellow, fading pink, obcordate to obovate, 3–5(–7) mm;

filaments 1–2 mm, anthers 0.5–1 mm;

style 1–2 mm, stigma surrounded by anthers at anthesis.

4-merous, zygomorphic, opening at sunset;

floral tube 10–11 mm;

sepals 11–15 mm;

petals white, fading pink, rhombic-obovate, 11–14 mm;

filaments 6.5–9 mm, anthers 2.5–4 mm, pollen 90–100% fertile;

style 22–28 mm, stigma exserted beyond anthers.

Capsules

ellipsoid-rhombic to subglobose, 4-angled, 4–6(–10) × 1.5–3 mm, stipe 0–4 mm, valve midrib raised at distal end, indehiscent or tardily dehiscent distally;

sessile.

ellipsoid or ovoid, sharply 4-angled, with deep furrows alternating with angles for 2–3 mm from apex, ribbed from base of furrow to base of fruit, 9–11 × 3–5 mm;

sessile.

Seeds

clustered in each locule, ovoid, surface minutely papillose, 1 × 0.5 mm.

2–4, yellowish to light brown, 2–3 mm.

2n

= 14.

= 14.

Oenothera linifolia

Oenothera dodgeniana

Phenology Flowering Apr–Jun(–Aug). Flowering Jun–Sep.
Habitat Prairies, open woodlands, open rocky and sandy sites, roadsides. Mountain meadow openings in coniferous forests.
Elevation 0–400 m. (0–1300 ft.) 1800–2700 m. (5900–8900 ft.)
Distribution
from FNA
AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; TX
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; NM
Discussion

Kneiffia linearifolia Spach (1835) is an illegitimate name based on Oenothera linifolia.

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

Oenothera dodgeniana occurs in two disjunct areas: the western foothills of the San Juan Mountains in Archuleta and Huerfano counties, Colorado, and Rio Arriba County, New Mexico; and Sierra Blanca and Sacramento Mountains in Lincoln and Otero counties, south-central New Mexico. The species was collected once at Durango, La Plata County, Colorado (P. H. Raven and D. P. Gregory 1972[1973]), but has not since been recollected. Oenothera dodgeniana and O. coloradensis were considered by Raven and Gregory to represent a relict species along the eastern flank of the Rocky Mountains that arose from more widespread species farther to the east, such as O. filiformis. Oenothera dodgeniana belongs to a subclade which is sister to that containing O. coloradensis, and within that subclade is sister to O. demareei and O. lindheimeri (W. L. Wagner et al. 2013). Although O. dodgeniana is fairly closely related to O. coloradensis, the two taxa seem to have had independent origins that have led to distributions along the eastern flank of the Rocky Mountains. Oenothera dodgeniana is self-compatible (Raven and Gregory).

(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. Peniophyllum Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Gaura > subsect. Gaura
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. 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. 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 Kneiffia linifolia, O. linifolia var. glandulosa, Peniophyllum linifolium Gaura neomexicana, O. coloradensis subsp. neomexicana
Name authority Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821) Krakos & W. L. Wagner: PhytoKeys 28: 66. (2013)
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