Flora of North America species comparison

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Oenothera linifolia

Oenothera sect. Peniophyllum

threadleaf evening-primrose, threadleaf sundrop
Habit Herbs annual, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot. Herbs annual, caulescent; from a taproot.
Stems

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

erect, unbranched or branched.
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, cauline 1–2(–)4 cm;

blade margins subentire or remotely dentate.
Inflorescences

solitary flowers in axils of distal leaves.
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.

opening near sunrise, nearly unscented;

buds erect, terete, without free tips;

floral tube 1–2 mm;

sepals separating in pairs;

petals bright yellow, fading pink, obcordate to obovate;

stigma shallowly divided into 4 linear lobes.
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.

hard and leathery, ellipsoid-rhombic to subglobose, 4-angled, apex rounded or obtuse, proximal part tapering to a sterile, pedicel-like base (stipe), valve midrib raised at distal end, indehiscent or tardily dehiscent distally;

sessile.
Seeds

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

usually numerous, clustered in each locule, ovoid, surface minutely papillose.
2n

= 14.

= 14.

Oenothera linifolia

Oenothera sect. Peniophyllum
Phenology Flowering Apr–Jun(–Aug).
Habitat Prairies, open woodlands, open rocky and sandy sites, roadsides.
Elevation 0–400 m. (0–1300 ft.)
Distribution
from FNA
AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; TX
[WildflowerSearch map]
[BONAP county map]
sc United States; se United States
Discussion

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

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

Species 1.

Section Peniophyllum consists of a single diploid species. It has been treated as the sole member of subg. Kneiffia sect. Peniophyllum (P. A. Munz 1937, 1965) or sect. Kneiffia subsect. Peniophyllum (G. B. Straley 1977). It was separated from sect. Kneiffia by W. L. Wagner et al. (2007) because molecular data (R. A. Levin et al. 2004) failed to place these two groups in a single clade. Instead, Oenothera linifolia forms a very weakly supported clade with O. havardii (sect. Paradoxus), with which it shares no known morphological similarity other than characteristics of subclade B. The most distinctive characteristics of sect. Peniophyllum are the heteromorphic rosette versus cauline leaves, the cauline leaves crowded and linear, capsules ellipsoid-rhombic to subglobose, indehiscent or tardily dehiscent only at distal end, and the entire capsule falling from the plant prior to senescence. In most sections of Oenothera, the capsules are persistent on the stem, but in sect. Peniophyllum and two other sections (Gaura and Megapterium) of subclade B, the capsules often disarticulate from the plant. The flowers are self-compatible, diurnal, and autogamous or cleistogamous.

(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
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
Subordinate taxa
Synonyms Kneiffia linifolia, O. linifolia var. glandulosa, Peniophyllum linifolium Peniophyllum, O. section peniophyllum
Name authority Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821) (Pennell) Munz: Bull. Torrey Bot. Club 64: 288. (1937)
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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