Crocanthemum suffrutescens

(B. Schreiber) Sorrie

Phytologia 93: 271. 2011.

Common names: Ione rushrose
Endemic
Basionym: Helianthemum suffrutescens B. Schreiber Madroño 5: 81, fig. 1. 1939
Treatment appears in FNA Volume 6. Treatment on page 408. Mentioned on page 401, 402.

Subshrubs. Stems erect, 35–80 cm, usually stellate-pannose, sometimes sparsely stellate-pubescent. Leaves cauline, tending to persist in summer; petiole 0–1 mm; blade linear to lanceolate, 10–30(–43) × 2–8 mm, surfaces stellate-pannose, lateral veins obscure abaxially. Inflorescences terminal, narrow panicles, usually stellate-pannose, sometimes sparsely stellate-pubescent; chasmogamous flowers 8–20 per panicle, cleistogamous 0. Pedicels 1–9 mm, sparsely or not glandular-hairy; bracts 5–25 × 0.3 mm. Chasmogamous flowers: outer sepals linear, 2 × 0.2 mm, inner sepals 5–7(–8) × 2.5–3.5 mm, apex acute to acuminate; calyx stellate-pubescent, hairs to 1 mm; petals obovate, 6–9 × 5–7 mm; capsules 3.5–4.3 × 2.5–2.7 mm, glabrous.


Phenology: Flowering Apr–Jun.
Habitat: Xeric to dry chaparral in shallow soil of Ione Formation
Elevation: 100–700 m

Discussion

Crocanthemum suffrutescens is known from Amador and Calaveras counties, where it is often associated with Arctostaphylos myrtifolia, grasses, and shrub oaks. The remarkable soils of the Ione Formation harbor other localized endemics, including A. myrtifolia, Eriogonum apricum, and Horkelia parryi.

Crocanthemum suffrutescens is similar to C. aldersonii in its tall habit, paniculate inflorescence, and long sepals; it differs in its denser stellate tomentum, shorter and straight inflorescence branches, smaller corollas, and thickened bases to the stellate hairs of the calyx. Leaves of C. suffrutescens tend to persist through summer; they tend to drop in C. aldersonii and C. scoparium; these are tendencies only and cannot be relied on for identification.

Selected References

None.

Lower Taxa

None.