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

rosemary frostweed

Alderson rushrose, Alderson's rush-rose

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.

Crocanthemum rosmarinifolium

Crocanthemum aldersonii

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
from FNA
AL; AR; FL; GA; LA; MS; NC; OK; SC; TX; West Indies (Dominican Republic)
[BONAP county map]
from FNA
CA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
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
C. aldersonii, C. arenicola, C. bicknellii, C. canadense, C. carolinianum, C. corymbosum, C. dumosum, C. georgianum, C. glomeratum, C. greenei, C. nashii, C. propinquum, C. scoparium, C. suffrutescens
C. arenicola, C. bicknellii, C. canadense, C. carolinianum, C. corymbosum, C. dumosum, C. georgianum, C. glomeratum, C. greenei, C. nashii, C. propinquum, C. rosmarinifolium, C. scoparium, C. suffrutescens
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)
Web links