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evening primrose

Habit Herbs,usually annual, rarely short-lived perennial, caulescent.
Stems

prostrate to ascending or erect, often with reddish brown or white exfoliating epidermis.

Leaves

cauline and often in a basal rosette, alternate;

stipules absent;

sessile or petiolate;

blade margins dentate, denticulate, or serrulate.

Inflorescences

spikes, erect or nodding at anthesis.

Flowers

bisexual, actinomorphic, buds erect;

floral tube deciduous (with sepals, petals, and stamens) after anthesis, with basal nectary;

sepals 4, usually reflexed in pairs, sometimes separately;

petals 4, yellow, fading red, with 1+ red dots basally;

stamens 8, in 2 unequal series, anthers versatile, pollen shed singly;

ovary 4-locular, without apical projection, style glabrous or pubescent distally, stigma entire, subcapitate to subglobose, surface unknown, probably wet and non-papillate.

Fruit

a capsule, contorted or curled 1 to 5 times, or straight, narrowly cylindrical and thickened proximally, 4-angled (at least when dry), regularly but tardily loculicidally dehiscent, not swollen by seeds;

sessile.

Seeds

numerous, in 1 row per locule, flattened, narrowly obovoid, dull.

xI> = 7.

Camissoniopsis

Distribution
w United States; nw Mexico
[BONAP county map]
Discussion

Species 14 (13 in the flora).

Camissoniopsis proavita (P. H. Raven) W. L. Wagner & Hoch is known from northern Baja California, Mexico. It is a diploid, closely related to C. micrantha but differing in having numerous flowers in the basal rosette, which is densely leafy.

All species of Camissoniopsis occur near coasts or on dry slopes or desert flats inland from 0–2500 m. R. A. Levin et al. (2004) found strong molecular support for Camissoniopsis in a clade with Neoholmgrenia and Tetrapteron. Camissoniopsis was segregated from Camissonia as delimited by P. H. Raven (1969). Camissoniopsis is distinguished by having 4-angled fruits, at least when dry, and not swollen by seeds, dull seeds usually smaller than 1 mm, and by flowering from both basal and distal nodes (Raven). Relationships within Camissoniopsis are complex and reticulate. Several diploids (especially C. hirtella) appear to have contributed to the formation of the tetraploids and, in turn, the hexaploids (Raven), and, as a result, are very similar morphologically to each other. Identification of the polyploid species of Camissoniopsis is aided by their pollen having a high proportion of grains with higher number of pores than typical Onagraceae 3-pored pollen, usually 4- or 5-pored. This can be observed under low magnification (for example, 10\×) since the 3-pored pollen is triangular while the 4-pored is quadrangular and 5-pored is pentangular. Raven proposed Camissonia sect. Holostigma as a new combination based on Spach’s generic name. He was unaware that Holostigma Spach, like Agassizia Spach, is a later homonym and thus illegitimate; however, he satisfied all requirements for valid publication of a new sectional name in Camissonia. Reproductive features include: self-incompatible (C. cheiranthifolia and C. bistorta) or self-compatible; flowers diurnal; outcrossing and pollinated by bees (E. G. Linsley et al. 1963, 1964, 1973) or autogamous (Raven).

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

Key
1. Herbs perennial; coastal habitats.
C. cheiranthifolia
1. Herbs usually annual, rarely short-lived perennial (in C. bistorta); primarily inland habitats.
→ 2
2. Stigma exserted beyond anthers at anthesis; sepals (2.3–)5–8(–11) mm; petals (4.2–)7–15 mm.
C. bistorta
2. Stigma surrounded by all anthers, or at least those of longer filaments, at anthesis; sepals 1–6(–8.5) mm; petals 1.5–10.5(–13) mm.
→ 3
3. Capsules 2.8–3.5 mm diam. near base, straight or slightly curved outward, deeply grooved along lines of dehiscence.
C. guadalupensis
3. Capsules 0.7–2.2 mm diam. near base, straight or curved into 1+-coiled spirals, not deeply grooved.
→ 4
4. Pollen with 25–100% of grains 4- or 5-pored.
→ 5
5. Inflorescences exclusively villous; 25–60% of pollen grains 4- or 5-pored.
C. luciae
5. Inflorescences villous and glandular puberulent; 70–100 % of pollen grains 4- or 5-pored.
→ 6
6. Capsules 1.3–1.6 mm diam., subterete in living material (obscurely 4-angled when dry); southernmost Monterey County to central San Luis Obispo County, California.
C. hardhamiae
6. Capsules 1.5–2 mm diam., 4-angled in living material; San Diego County, California, adjacent Baja California, and offshore islands.
C. robusta
4. Pollen with less than 5% of grains 4-pored (rarely more in C. intermedia).
→ 7
7. Capsules 1.8–2.2 mm diam., conspicuously 4-angled in living material.
C. lewisii
7. Capsules 0.7–1.2(–1.8) mm diam., terete, subterete, or obscurely 4-angled, at least in living material.
→ 8
8. Distal leaves petiolate, blade base attenuate; capsules usually much contorted, irregularly to 5-coiled; herbs moderately to sparsely strigillose, sometimes also sparsely villous.
C. ignota
8. Distal leaves usually subsessile, blade base rounded, cuneate, or truncate; capsules straight to 1–2-coiled; herbs strigillose to villous.
→ 9
9. Herbs conspicuously grayish in appearance, densely strigillose; lateral stems usually decumbent; plants of the deserts.
C. pallida
9. Herbs not conspicuously gray in appearance, mostly villous; lateral stems erect to decumbent; plants not of deserts or only at desert margins (except C. confusa in central Arizona).
→ 10
10. Capsules 0.7–0.9 mm diam.; distal leaf blades elliptic-ovate or ovate; stems ascending to erect.
C. hirtella
10. Capsules 0.9–1.2(–1.8) mm diam.; distal leaf blades narrowly lanceolate to narrowly ovate; stems decumbent or erect.
→ 11
11. Stems decumbent; inflorescences usually densely villous, rarely also glandular puberulent.
C. micrantha
11. Stems erect; inflorescences usually moderately to densely villous, also glandular puberulent.
→ 12
12. Floral tube (1.8–)2–3.8 mm; petals (2.5–)5–10.5 mm; styles (2.5–)4.5–7.5 mm; herbs densely villous, often also stigillose.
C. confusa
12. Floral tube 1.2–2 mm; petals 1.5–3.5(–4.5) mm; styles 2–3.5 mm; herbs moderately villous.
C. intermedia
Source FNA vol. 10. Author: Warren L. Wagner.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae
Subordinate taxa
C. bistorta, C. cheiranthifolia, C. confusa, C. guadalupensis, C. hardhamiae, C. hirtella, C. ignota, C. intermedia, C. lewisii, C. luciae, C. micrantha, C. pallida, C. robusta
Synonyms Agassizia, Camissonia section holostigma, Holostigma
Name authority W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 123. (2007)
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