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rosemary frostweed

island rush-rose

Habit Herbs. Subshrubs.
Stems

ascending to erect, (13–)20–40(–51) cm, stellate-tomentose.

erect, 15–30 cm, sparsely to densely stellate-pubescent, distally with dense, dark, glandular hairs 0.4–0.8 mm.

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 0–2.5 mm;

blade oblanceolate to linear-lanceolate, 7–25(–35) × 2–4(–7) mm, margins nonrevolute, surfaces stellate-pubescent, 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, corymbose; chasmogamous flowers 3–25 per corymb, cleistogamous 0.

Pedicels

10–22 mm;

bracts 3–7 × 0.5–1 mm.

1–4(–6) mm, stellate-pubescent and densely glandular-hairy;

bracts 3–10 × 0.5–1.5 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 lanceolate, 2.5–4 × 0.5–1 mm, inner sepals 4.5–8 × 3–4 mm, apex acuminate;

calyx strigose (sometimes also short-stellate-hairy), hairs simple, 1–1.7 mm;

petals obovate, 5–8 × 3–4 mm;

capsules 4.3–6 × 3–3.5 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 greenei

Phenology Flowering May–Jul. Flowering Apr–May.
Habitat Dry, sandy roadsides, openings in pine and pine-oak woodlands, disturbed soil of clearings and fields Dry, rocky ridges
Elevation 0–200 m (0–700 ft) 10–100 m (0–300 ft)
Distribution
from FNA
AL; AR; FL; GA; LA; MS; NC; OK; SC; TX; West Indies (Dominican Republic)
[BONAP county map]
from FNA
CA
[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 greenei has been documented from San Miguel, Santa Catalina, Santa Cruz, and Santa Rosa islands. According to the California Native Plant Society, it is extant on Santa Catalina, Santa Cruz, and Santa Rosa islands, totaling about 20 populations and listed federally as threatened. Threats are from non-native mammals and plants. The habit, dense, dark glandular hairs on stems and pedicels, and long, white hairs on the calyx distinguish C. greenei.

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

Source FNA vol. 6, p. 407. FNA vol. 6, p. 406.
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. aldersonii, C. arenicola, C. bicknellii, C. canadense, C. carolinianum, C. corymbosum, C. dumosum, C. georgianum, C. glomeratum, C. nashii, C. propinquum, C. rosmarinifolium, C. scoparium, C. suffrutescens
Synonyms Helianthemum rosmarinifolium, C. domingense, C. stenophyllum Helianthemum greenei
Name authority (Pursh) Janchen: in H. G. A. Engler et al., Nat. Pflanzenfam. ed. 2, 21: 307. (1925) (B. L. Robinson) Sorrie: Phytologia 93: 270. (2011)
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