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California primrose, California suncup

Habit Herbs, annual, [perennial, subshrubs], caulescent; with a taproot. Herbs sparsely strigillose, sometimes also sparsely glandular puberulent, especially on leaves and inflorescences.
Stems

erect [to prostrate], unbranched or branched.

erect, virgate, bluish green and often glaucescent, or bright green, thick, hollow, fleshy, 2–180 cm.

Leaves

cauline, sometimes also in basal rosette, alternate;

stipules absent;

sessile or petiolate;

blade pinnatifid to lobed, [subentire].

in a well-defined basal rosette, usually withered by anthesis, and also cauline;

basal 2.5–10(–30) × 0.6–2.5(–6.5) cm, petiole 0–6 cm, blade narrowly elliptic, margins irregularly pinnatifid;

cauline very much reduced distally, 1–8 × (0.1–)0.3–1(–1.6) cm, petiole 0–3 cm, blade narrowly elliptic, margins irregularly pinnatifid.

Inflorescences

open spikes, erect.

Flowers

bisexual, actinomorphic, buds erect;

floral tube relatively short, deciduous (with sepals, petals, and stamens) after anthesis, lined with a lobed, fleshy nectary disc [or with rounded, fleshy disc at base of style];

sepals 4, reflexed separately, in pairs, or as a unit, (rarely spreading);

petals 4, yellow, fading orangish red, usually finely flecked with red near base;

stamens 8, in 2 subequal series or epipetalous series shorter, anthers versatile, pollen shed singly;

ovary 4-locular, stigma globose to cylindrical, surface wet and non-papillate.

opening at sunrise;

floral tube 0.6–1.5 mm, closed by a conspicuous rounded, fleshy, reddish brown disc;

sepals reddish green, 3.9–8 mm;

petals ± with fine, red flecking at base, 6–14 mm; episepalous filaments 3–9 mm, epipetalous filaments 2–5 mm, anthers of longer stamens 1–2.5 mm, those of shorter stamens 0.5–1.2 mm;

style 4–10 mm, stigma globose, 0.8–2 mm diam., surrounded by anthers of longer stamens at anthesis.

Fruit

a capsule, straight or slightly curved [contorted], somewhat torulose or subterete, loculicidally dehiscent, midrib of each valve prominent;

sessile.

Capsules

sharply reflexed at maturity, cylindrical fresh, 4-angled dry, (45–)60–110 × 1–1.2 mm.

Seeds

numerous, in 1 row per locule, narrowly obovoid, ± triangular in cross section, finely papillose.

olive brown, often flecked with purple dots, 1.3–1.6 × 0.5–0.7 mm.

xI> = 7.

2n

= 14, 28.

Eulobus

Eulobus californicus

Phenology Flowering Dec–May.
Habitat Open places in coastal sage scrub, chaparral, desert scrub, valley grasslands, foot­hill woodlands, washes, flats, loose soils.
Elevation 0–1300 m. (0–4300 ft.)
Distribution
sw United States; nw Mexico
[BONAP county map]
from FNA
AZ; CA; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Species 4 (1 in the flora).

Eulobus is characterized by olive brown seeds with distinct purple spots, yellow petals with maroon flecks near the base, the distal part ultraviolet-reflective, leaves mostly lobed or pinnatifid, and capsules somewhat contorted or straight, and often sharply reflexed at maturity. R. A. Levin et al. (2004) included E. californicus and E. crassifolius (Greene) W. L. Wagner & Hoch (a species of Baja California, Mexico) in their molecular analysis and found Eulobus to be strongly supported as monophyletic; they also found that Eulobus plus (Chylismia plus Oenothera) formed a weakly supported clade. Reproductive features include: self-incompatible [E. crassifolius, E. sceptrostigma (Brandegee) W. L. Wagner & Hoch] or self-compatible [E. angelorum (S. Watson) W. L. Wagner & Hoch, E. californicus], flowers diurnal, outcrossing and pollinated mainly by small oligolectic bees (E. G. Linsley 1963b, 1973) or autogamous (P. H. Raven 1969).

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

Eulobus californicus is known from western and southern Arizona, central and southern California, as well as from adjacent areas of northwestern Mexico.

P. H. Raven (1969) determined that Eulobus californicus is self-compatible and primarily autogamous. Known diploid (2n = 14) populations are all in California.

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

Source FNA vol. 10. Author: Warren L. Wagner. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae Onagraceae > subfam. Onagroideae > tribe Onagreae > Eulobus
Subordinate taxa
E. californicus
Synonyms Camissonia section eulobus, Oenothera section eulobus, Oenothera subg. eulobus Camissonia californica, Oenothera leptocarpa
Name authority Nuttall ex Torrey & A. Gray: Fl. N. Amer. 1: 514. (1840) Nuttall ex Torrey & A. Gray: Fl. N. Amer. 1: 515. (1840)
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