The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

froststem suncup

Walker's evening-primrose, Walker's sun-cup

Habit Herbs annual or biennial, villous, at least proximally, glabrous or even glaucous distally, rarely glandular puberulent. Herbs annual or short-lived perennial, villous, usually densely so proximally, less dense to glabrate distally, sometimes hairs somewhat appressed and shorter on leaves, also sometimes glandular puberulent on distal parts.
Stems

virgate with numerous divergent branches, 20–150 cm.

slender, unbranched or branched from base, 10–60 cm.

Leaves

primarily in well-developed basal rosette, cauline reduced or absent, 6–30 × 1.4–6.5 cm;

petiole 0.3–6 cm;

blade pinnately or bipinnately lobed, terminal lobe ovate to elliptic, 2.5–6.5 × 1.5–3 cm, margins irregularly serrate, dark brown oil cells prominently lining veins abaxially.

in basal rosette and/or cauline, often purple-dotted, 2–22 × 0.4–3.5 cm;

petiole 0.4–8 cm;

blade pinnately lobed, sometimes lateral lobes greatly reduced or absent and blade reduced to terminal lobe only, terminal lobe oblong or cordate to ovate, 1–5 × 0.5–3.2 cm, margins serrate, brown oil cells prominently lining veins abaxially.

Racemes

erect to nodding, elongating in bud.

erect, elongating after anthesis.

Flowers

opening at sunrise;

buds individually reflexed, with apical or slightly subapical free tips less than 1 mm;

floral tube 1–3 mm, glabrous or villous inside proximally;

sepals 3–8 mm;

petals usually bright yellow, rarely cream, fading yellow to lavender, 4–9 mm;

stamens unequal, filaments of antisepalous stamens 2.5–4 mm, those of antipetalous ones 1.3–3 mm, anthers 2–4 mm, ciliate;

style 7–11 mm, stigma exserted beyond anthers at anthesis.

opening at sunrise;

buds individually reflexed, with apical free tips less than 1 mm;

floral tube 0.5–1.5 mm, glabrous or sparsely villous inside;

sepals 1.5–5 mm;

petals bright yellow, fading pale orange or lavender, 1–6 mm;

stamens unequal, filaments of antisepalous stamens 1–3 mm, those of antipetalous ones 0.3–2 mm, anthers 0.5–2 mm, glabrous or sparsely ciliate;

style 1.5–6 mm, stigma surrounded by anthers at anthesis.

Capsules

usually spreading, rarely slightly reflexed, oblong-cylindrical, 10–52 mm;

pedicel 7–20 mm.

spreading or ascending, oblong-cylindrical, 11–45 mm;

pedicel 5–30 mm.

Seeds

1–1.3 mm.

0.6–1.2 mm.

2n

= 14.

Chylismia multijuga

Chylismia walkeri

Phenology Flowering Mar–Jun(–Sep).
Habitat Forming colonies on rocky slopes and banks of eroded sedimentaries, on gypsum or limestone, on conglomerates, often with Juniperus and Pinus edulis, with Encelia farinosa and Larrea.
Elevation 300–1100 m. (1000–3600 ft.)
Distribution
from FNA
AZ; NV; UT
[WildflowerSearch map]
[BONAP county map]
sw United States
[WildflowerSearch map]
[BONAP county map]
Discussion

Chylismia multijuga is known from Washington County, Utah, and southern Lincoln County, Nevada, to northern Mohave County, Arizona. P. H. Raven (1962, 1969) determined this species to be self-incompatible. It hybridizes with C. brevipes subspp. brevipes and pallidula.

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

Subspecies 2 (2 in the flora).

P. H. Raven (1962, 1969) determined this species to be self-incompatible and primarily autogamous.

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

Key
1. Leaves primarily cauline, rarely forming inconspicuous basal rosette, lateral lobes usually greatly reduced or absent; petals 1–3 mm; anthers 0.5–0.8 mm.
subsp. walkeri
1. Leaves primarily basal, forming conspicuous rosette, cauline reduced or absent, lateral lobes usually well developed; petals 2.8–6 mm; anthers 1–2 mm.
subsp. tortilis
Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Chylismia > sect. Chylismia Onagraceae > subfam. Onagroideae > tribe Onagreae > Chylismia > sect. Chylismia
Sibling taxa
C. arenaria, C. atwoodii, C. brevipes, C. cardiophylla, C. claviformis, C. confertiflora, C. eastwoodiae, C. exilis, C. heterochroma, C. megalantha, C. munzii, C. parryi, C. scapoidea, C. specicola, C. walkeri
C. arenaria, C. atwoodii, C. brevipes, C. cardiophylla, C. claviformis, C. confertiflora, C. eastwoodiae, C. exilis, C. heterochroma, C. megalantha, C. multijuga, C. munzii, C. parryi, C. scapoidea, C. specicola
Subordinate taxa
C. walkeri subsp. tortilis, C. walkeri subsp. walkeri
Synonyms Oenothera multijuga, Camissonia multijuga, Chylisma hirta, C. parviflora, C. venosa, O. brevipes var. multijuga, O. brevipes var. parviflora, O. multijuga var. parviflora, O. phlebophylla, O. watsonii Camissonia walkeri, Oenothera walkeri
Name authority (S. Watson) Small: Bull. Torrey Bot. Club 23: 193. (1896) — (as Chylisma) A. Nelson: Bot. Gaz. 56: 66. (1913) — (as Chylisma)
Web links