Crocanthemum rosmarinifolium |
Crocanthemum aldersonii |
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rosemary frostweed |
Alderson rushrose, Alderson's rush-rose |
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Habit | Herbs. | Subshrubs. |
Stems | ascending to erect, (13–)20–40(–51) cm, stellate-tomentose. |
erect, 30–65 cm, glabrate to sparsely stellate-pubescent. |
Leaves | cauline and, sometimes, basal basal mat-forming; petiole 1–3 mm; blade obovate, 10–22 × 3–5 mm; cauline: petiole 1–4 mm; blade oblanceolate to narrowly lanceolate, 10–38(–48) × 2–5.5(–7.8) mm, margins revolute; surfaces stellate-tomentose abaxially, stellate-pubescent adaxially, without simple hairs; lateral veins obscure abaxially. |
cauline; petiole 0.5–1.5 mm; blade linear, 10–21(–26) × 0.9–2 mm, surfaces stellate-pannose, lateral veins obscure abaxially. |
Inflorescences | axillary and terminal, solitary flowers or glomerules; chasmogamous flowers solitary, at tips of branches, overtopping cleistogamous, cleistogamous 2–7 per glomerule, flowering 1–3 months later than chasmogamous. |
terminal, broad panicles, branches spreading, usually curved, stellate-pannose; chasmogamous flowers 1–3 per branch; cleistogamous 0. |
Pedicels | 10–22 mm; bracts 3–7 × 0.5–1 mm. |
5–13 mm, stellate-pubescent with no or sparse glandular hairs; bracts 1–2.5 × 0.3–0.5 mm. |
Chasmogamous | flowers: outer sepals linear, 1.2–2.5 × 0.2 mm, inner sepals 2.5–4.3 × 1.3–2 mm, apex acute; petals obovate, 4–6 × 3.5–5 mm; capsules 2–3 × 1.4–1.8 mm, glabrous. |
flowers: outer sepals linear, 1.3–2(–2.8) × 0.3 mm, inner sepals 4.7–7(–8) × 2–3 mm, apex acuminate or acute, calyx stellate-pubescent, hairs to 1 mm; petals obovate, 8–12 × 6–8 mm; capsules 3.5–4.3 × 2.3–2.7 mm, glabrous. |
Cleistogamous | flowers: outer sepals linear, 0.5–1 × 0.2 mm, inner sepals ovate, 1.5–1.8 × 1–1.5 mm, apex acute; capsules 1.3–1.7 × 1–1.3 mm, glabrous. |
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Crocanthemum rosmarinifolium |
Crocanthemum aldersonii |
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Phenology | Flowering May–Jul. | Flowering Mar–Jun. |
Habitat | Dry, sandy roadsides, openings in pine and pine-oak woodlands, disturbed soil of clearings and fields | Chaparral on slopes and in canyons |
Elevation | 0–200 m (0–700 ft) | 100–1200 m (300–3900 ft) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; OK; SC; TX; West Indies (Dominican Republic) |
CA; Mexico (Baja California)
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Discussion | Crocanthemum rosmarinifolium is easily distinguished from sympatric species by its slender leaves, relatively small petaliferous flowers, occasional basal leaves, and overall pale color. As noted by R. M. Harper over a century ago, it seems not to occupy natural habitats and is found primarily on roadsides. Populations in the Dominican Republic occur up to at least 2200 m. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Crocanthemum aldersonii occurs from Orange and San Bernardino counties south into Baja California. Although traditionally placed within a broadly circumscribed C. scoparium, the tall habit, paniculate inflorescence, and acuminate to acute inner sepals of C. aldersonii are more similar to those of C. suffrutescens. The calyx of C. aldersonii occasionally has stellate hairs with thickened bases, a characteristic always present in C. suffrutescens. The tall inflorescence, curved inflorescence branches, and relatively large corollas are unique among Pacific slope species of Crocanthemum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 6, p. 407. | FNA vol. 6, p. 402. |
Parent taxa | Cistaceae > Crocanthemum | Cistaceae > Crocanthemum |
Sibling taxa | ||
Synonyms | Helianthemum rosmarinifolium, C. domingense, C. stenophyllum | Helianthemum aldersonii, H. scoparium var. aldersonii |
Name authority | (Pursh) Janchen: in H. G. A. Engler et al., Nat. Pflanzenfam. ed. 2, 21: 307. (1925) | (Greene) Janchen: in H. G. A. Engler et al., Nat. Pflanzenfam. ed. 2, 21: 305. (1925) |
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