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California evening primrose

Habit Herbs perennial (short-lived or, sometimes, suffrutescent) or annual, glabrous or strigillose; from a stout taproot. Herbs perennial, densely strigillose, sometimes also villous, or glabrous; from a taproot, lateral roots producing adventitious shoots, or rarely with fleshy underground horizontal rootstock (subsp. eurekensis).
Stems

1–many, weakly decumbent to ascending or erect, unbranched to moderately branched, (10–)25–80 cm.

ascending or decumbent, usually branched from near base, sometimes new rosettes forming at branch apex when buried in drifting sand, 10–60 cm.

Leaves

1–9 × (0.1–)0.3–1 cm, sometimes fascicles of small leaves to 2 cm present in non-flowering axils;

petiole 0–0.6 cm;

blade linear to narrowly lanceolate or oblanceolate, often folded lengthwise, usually not much reduced distally, proximalmost leaves sometimes spatulate, base attenuate, margins subentire or serrulate or spinulose-serrate, apex acute.

in a basal rosette and cauline, rosette sometimes weakly developed or absent, at least during flowering, 1–13 × 0.5–2 cm;

petiole 0–2(–4.5) cm;

blade oblong to oblanceolate or spatulate, sometimes rhombic-ovate, margins entire or weakly to conspicuously dentate or pinnatifid.

Flowers

opening at sunrise;

buds with free tips 0–4 mm;

floral tube 5–20 mm;

sepals 4–12 mm, midribs keeled;

petals yellow, fading orangish to purplish, 6–25 mm; antisepalous filaments 2–8 mm, antipetalous filaments 1–4 mm, anthers 2–7 mm, pollen 90–100% fertile;

style 9–30 mm, stigma sometimes blue-black, discoid to quadrangular, exserted beyond anthers.

1–several opening per day near sunset;

buds nodding, weakly quadrangular, with free tips 0–0.8 mm;

floral tube 20–40 mm;

sepals 15–30 mm, not spotted;

petals white, fading pink to deep pink, broadly obcordate, 15–35(–40) mm;

filaments 10–17 mm, anthers 5–10 mm;

style 30–60 mm, stigma exserted beyond anthers at anthesis.

Capsules

10–35 × 1–2 mm, hard, dehiscent 1/2 their length, often tardily dehiscent throughout their length.

spreading to ascending, woody in age, often curved upward, cylindrical, obtusely 4-angled, tapering slightly from base to apex, 20–80 × 2–3.5 mm;

sessile.

Seeds

obovoid, 1–1.8 mm, sharply angled, apex truncate.

numerous, in 1 row per locule, olive-brown or yellowish brown to black, sometimes with minute purple dots, obovoid, 1–2.5 mm.

Oenothera capillifolia

Oenothera californica

Distribution
c United States; sc United States; n Mexico
from USDA
w United States; nw Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Subspecies 2 (2 in the flora).

Oenothera capillifolia is self-incompatible (H. F. Towner 1977).

Oenothera berlandieri (Spach) Steudel 1841, not D. Dietrich 1840, is superfluous and cannot be used in Oenothera when transferred from Calylophus, and pertains here.

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

Subspecies 3 (3 in the flora).

Most populations of Oenothera californica are self-incompatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010), but some populations of subsp. californica are self-compatible. All chromosome counts indicate that subspp. avita and eurekensis are diploid (2n = 14) and those of subsp. californica are tetraploid (2n = 28). Oenothera californica is polymorphic with subspp. avita and californica being very similar, and differing primarily in ecology, distribution, and relatively minor differences in leaf morphology and ploidy level, while the sand dune-restricted subsp. eurekensis is more distinctive in both morphology and habitat.

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

Key
1. Stems 1–several, ascending to erect, 30–80 cm; leaves 2.5–9 cm.
subsp. capillifolia
1. Stems several–many, decumbent to ascending, (10–)25–40 cm; leaves 1–4 cm.
subsp. berlandieri
1. Plants with fleshy underground horizontal rootstocks; stems sometimes with new rosettes forming at stem apex when becoming buried in drifting sand; leaf blades rhombic-ovate to oblanceolate, margins entire or weakly dentate.
subsp. eurekensis
1. Plants with a taproot and adventitious shoots from lateral roots; stems not with new rosettes forming at branch apex; leaf blades oblong to oblanceolate to spatulate, margins entire or weakly to conspicuously dentate or pinnatifid.
→ 2
2. Leaf blade margins usually entire or weakly dentate, sometimes more conspicuously dentate to pinnatifid; capsules 30–55 mm.
subsp. californica
2. Leaf blade margins conspicuously dentate to pinnatifid, rarely some or all of them entire or weakly dentate; capsules 20–80 mm.
subsp. avita
Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Calylophus > subsect. Calylophus Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Anogra
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. 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
O. acutissima, O. albicaulis, O. argillicola, O. arida, O. arizonica, O. biennis, O. boquillensis, O. brachycarpa, O. calcicola, 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
Subordinate taxa
O. capillifolia subsp. berlandieri, O. capillifolia subsp. capillifolia
O. californica subsp. avita, O. californica subsp. californica, O. californica subsp. eurekensis
Synonyms Meriolix capillifolia O. albicaulis var. californica, Anogra californica, O. pallida var. californica
Name authority Scheele: Linnaea 21: 576. (1848) (S. Watson) S. Watson in W. H. Brewer et al.: Bot. California 1: 223. (1876)
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