Flora of North America species comparison

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Oenothera pilosella

Oenothera lindheimeri

meadow evening-primrose

Lindheimer's beeblossom
Habit Herbs perennial, usually densely to sparsely hirsute, rarely glabrous; from a thickened base, rhizomatous. Herbs clumped perennial, villous, usually more densely so proximally, hairs erect or ± appressed on leaf blades, also glandular puberulent distally, rarely glabrate; from taproot.
Stems

spreading or ascending, unbranched or few-branched distally, 20–80 cm.

many from base, ascending or erect, usually branched, 50–150 cm.
Leaves

in a basal rosette and cauline, basal 4–8 × 2–5 cm, petiole (0.5–)1–3(–4) cm, blade oblanceolate to ovate, margins entire;

cauline 3–10(–13) × 1–2(–4) cm, petiole 0–0.5(–2) cm, blade lanceolate to ovate, abruptly narrowed to base, margins subentire or coarsely dentate.

in a basal rosette and cauline, 0.5–9 × 0.
Inflorescences

erect, flowers in axils of distalmost few nodes.

Flowers

opening near sunrise;

buds with free tips 1–3 mm, spreading;

floral tube 10–25 mm;

sepals 10–20 mm;

petals bright yellow, fading pale pink or pale yellow, 15–30 mm;

filaments 7–15 mm, anthers 4–8 mm, pollen 85–100% fertile;

style 10–20 mm, stigma exserted beyond anthers at anthesis.

4-merous, zygomorphic, opening at sunrise;

floral tube 4–9 mm;

sepals 9–17 mm;

petals white, fading light or deep pink, rhombic-obovate to elliptic, 10–15 mm;

filaments 7–12 mm, anthers 3.5–4.5 mm, pollen 90–100% fertile;

style 16–27 mm, stigma exserted beyond anthers at anthesis.
Capsules

usually oblong-clavate to oblong-ellipsoid or ellipsoid, 4-angled or weakly 4-winged, (5–)10–15(–28) × 2–4(–5) mm, stipe (1–)3–5(–9) mm;

sessile.

ellipsoid or ovoid, 4-angled, 6–9 × 2–3.5 mm;

sessile.
Seeds

1 × 0.5 mm.

1–4, yellowish to light brown, 2–3 × 1–1.5 mm.
1

–1.3 cm;

blade narrowly elliptic to narrowly oblanceolate, margins coarsely and remotely serrate.
2n

= 56.

= 14.

Oenothera pilosella

Oenothera lindheimeri
Phenology Flowering May–Jul(–Aug). Flowering Apr–Jul(–Oct).
Habitat Open fields, edge of woods, marshes and bottomland prairies, open dis­turbed sites, ditches, old fields, railroads, roadsides. Black soil in coastal prairies.
Elevation 100–600 m. (300–2000 ft.) 0–100 m. (0–300 ft.)
Distribution
from FNA
AL; AR; CT; IA; IL; IN; KY; LA; MA; ME; MI; MO; MS; NH; NY; OH; OK; PA; RI; VA; VT; WI; WV; ON
[WildflowerSearch map]
[BONAP county map]
from FNA
LA; TX
[BONAP county map]
Discussion

Oenothera pilosella is widespread in cultivation in gardens and frequently escapes and becomes naturalized; the northern and eastern natural limits of O. pilosella are not clear. According to G. B. Straley (1977) the natural limits are from Wayne County, West Virginia, along the Ohio River and Erie County, New York, for the eastern limits, and Tuscola County, Michigan, and Manitowoc County, Wisconsin, for the northern limits. K. N. Krakos (2014), based on new field studies and phylogenetic data, found that O. pilosella does not form a monophyletic group with plants previously treated by Straley as O. pilosella subsp. sessilis in molecular analyses, and thus is here reinstated as the distinct species O. sessilis. Straley determined that O. pilosella is self-incompatible and an octoploid, one of the few in the genus.

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

Oenothera lindheimeri has a fairly narrow distribution and occurs only in Acadia, Allen, Beauregard, Calcasieu, Jefferson Davis, Lafayette, St. Mary, Tangipahoa, and Vermillion parishes in Louisiana, and Brazoria, Brazos, Chambers, Fort Bend, Galveston, Hardin, Harris, Jasper, Jefferson, Liberty, Orange, Victoria, and Victoria counties in Texas.

P. H. Raven and D. P. Gregory (1972[1973]) found Oenothera lindheimeri to be self-incompatible. It occasionally forms hybrids with O. filiformis. This species is widely cultivated and has many different cultivars.

(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. Kneiffia 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. 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. 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. 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 fruticosa var. pilosella, K. pilosella, K. pratensis, K. sumstinei, O. fruticosa var. hirsuta, O. fruticosa var. pilosella, O. pratensis Gaura lindheimeri, G. filiformis var. munzii
Name authority Rafinesque: Ann. Nat. 1: 15. (1820) (Engelmann & A. Gray) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 213. (2007)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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