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threadleaf evening-primrose, threadleaf sundrop

linda tarde, scarlet beeblossom, scarlet evening-primrose, scarlet gaura, wild honeysuckle

Habit Herbs annual, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot. Herbs perennial, densely strigillose, sometimes also long-villous proximally, sometimes glabrate; from a deep, thick taproot, often with branching underground stems, or branching only at surface, these often becoming horizontal or nearly so and giving rise to new plants.
Stems

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

erect or ascending, usually many-branched, 10–120 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 (but not present at flowering) and cauline, 0.7–6.5 × 0.1–1.5 cm, blade linear to narrowly elliptic, margins entire or remotely and coarsely serrate.

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 near sunset;

floral tube 4–11(–13) mm;

sepals 5–9(–10) mm;

petals white, fading salmon pink to scarlet-red, slightly unequal, obovate to elliptic-obovate or elliptic, 3–7(–8) mm, abruptly clawed;

filaments 3–6.5(–7) mm, anthers (2.5–)3–5(–5.5) mm;

style 10–22 mm, stigma exserted beyond anthers at anthesis.

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.

erect, pyramidal in distal 1/2 and abruptly constricted to terete proximal part, pyramidal part weakly or strongly angled, not conspicuously bulging at base, 4–9 × (1–)1.5–3 mm;

sessile.

Seeds

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

(1–)3 or 4, light to reddish brown, 1.5–3 × 1–1.5 mm.

2n

= 14.

= 14, 28, 42, 56.

Oenothera linifolia

Oenothera suffrutescens

Phenology Flowering Apr–Jun(–Aug). Flowering Apr–Aug(–Nov).
Habitat Prairies, open woodlands, open rocky and sandy sites, roadsides. Sandy or clay soil, often calcareous, desert shrublands to pinyon-juniper or oak woodlands, grasslands, disturbed areas.
Elevation 0–400 m. (0–1300 ft.) 150–2000(–3000) m. (500–6600(–9800) 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
AZ; CA; CO; IA; IL; IN; KS; MI; MN; MO; MT; ND; NE; NM; NV; NY; OK; SD; TX; UT; WI; WY; AB; BC; MB; ON; SK; Mexico (Aguascalientes, Chihuahua, Coahuila, Durango, Guanajuato, Hidalgo, Jalisco, México, Nuevo León, Oaxaca, Puebla, San Luis Potosí, Sonora, Tamaulipas, Veracruz, Zacatecas); intro­duced in South America (Brazil); Europe (Wales)
[WildflowerSearch map]
[BONAP county map]
Discussion

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

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

Oenothera suffrutescens is naturalized sporadically in southern California (Los Angeles, San Diego, Santa Barbara, and Ventura counties; although native in eastern part of the state), Illinois, Indiana, Michigan, New York, southern Ontario, and Wisconsin.

P. H. Raven and D. P. Gregory (1972[1973]) determined Oenothera suffrutescens to be self-incompatible and polyploid. It is known to form hybrids with O. calcicola and O. hispida.

Schizocarya kunthii Spach is an illegitimate name based on Gaura epilobioides that pertains here.

(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. Campogaura
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. 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. 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 suffrutescens, G. bracteata, G. coccinea, G. coccinea var. arizonica, G. coccinea var. epilobioides, G. coccinea var. glabra, G. coccinea var. integerrima, G. coccinea var. parvifolia, G. epilobioides, G. glabra, G. induta, G. linearis, G. marginata, G. multicaulis, G. odorata, G. parvifolia, G. spicata
Name authority Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821) (Seringe) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 214. (2007)
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