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John W. Thieret & Elizabeth McClintock, final revision by Thomas J. Rosatti & Bruce G. Baldwin, except as noted

Annual to shrub, aromatic, of sunny areas, often sandy or chalky substrates; hairs nonglandular, in stellate clumps or not, peltate or not, and/or glandular. Leaf: simple, alternate or opposite [whorled], often ± reduced, entire or not, petioled or not, stipuled or not. Inflorescence: raceme- or panicle-like cymes or flowers 1. Flower: generally bisexual, ± radial; sepals 3 or 5 (outer 2 often narrower), free or fused at very base, often persistent in fruit, 3 twisted in direction opposite that of petals; petals [0(3)]4–5, generally ephemeral; stamens (3–10) many, free, often sensitive to touch, ± persistent in fruit or not; ovary superior, chambers 1 (or ± 3–12 from intruded parietal placentas), style 0–1, stigma 1(3), lobes 0 or 3–12. Fruit: loculicidal capsule, valves 3–12. Seed: [1–]3–many.
8 genera, ± 175 species: temperate, especially southeastern United States, Mediterranean; some cultivated (Cistus; Crocanthemum; Tuberaria). [Arrington 2004 Ph.D. Dissertation Duke Univ] Flowers open in sunshine for < 1 day. Taxa of Helianthemum in TJM2 treated here in Crocanthemum. —Scientific Editors: Thomas J. Rosatti, Bruce G. Baldwin.
Unabridged references: [Strother FNANM, in press]

Key to Cistaceae


Bruce A. Sorrie & Thomas J. Rosatti

Perennial herb or subshrub, deciduous, generally late summer, fall; hairs generally in stellate clumps, rarely glandular (except inflorescence), sparse to dense. Stem: generally erect, ± broom-like. Leaf: basal 0 [present]; cauline generally alternate, generally linear to lanceolate or oblanceolate, sessile to short-petioled, margins entire, generally rolled under, stipules 0. Inflorescence: raceme- or panicle-like, glandular hairs on branches, pedicels generally 0 to sparse; cleistogamous flowers 0 [present]. Flower: sepals 5, outer 2 generally narrower; petals yellow; stamens 10–many; style < 2 mm, stigma ± hemispheric. Fruit: generally ± ovoid; valves generally 3.
21 species: North America to South America. (Greek: yellow flower) [Sorrie 2012 Phytologia 93:270–271] Esp abundant after fire, resprouting from woody caudex. New World taxa transferred from polyphyletic Helianthemum by Sorrie. Descriptions refer to opening flowers; cleistogamous flowers (0 in California), sometimes produced later, lack petals. Flowers of Crocanthemum scoparium from Mt. Diablo reported to have 5 stamens, which instead seem to represent 5 united pairs.
Unabridged note: Based on molecular and other data (as yet unpublished, by Jenny Arrington & Paul Manos) Helianthemum is polyphyletic; California taxa more closely related to Crocanthemum and Hudsonia than to Helianthemum; New World members treated in Crocanthemum by Sorrie, who is preparing treatment for FNANM.

Key to Crocanthemum

C. aldersonii (Greene) Janch. ALDERSON'S RUSH-ROSE
Stem: 30–65 cm. Leaf: petiole 0.5–1.5 mm; blade 10–21(26) mm, 0.9–2 mm wide. Flower: outer sepals 1.3–2(2.8) mm, ± 0.3 mm wide, linear, inner 4.7–7(8) mm, 2–3 mm wide, acuminate (acute); petals 8–12 mm, obovate; stamens 12–36. Fruit: 3.5–4 mm. Seed: 7–12.
Slopes, canyons in chaparral; 100–1200 m. South Coast, Peninsular Ranges; northern Baja California. [Helianthemum aldersonii Greene; Helianthemum scoparium Nutt. var. aldersonii (Greene) Munz; Helianthemum scoparium Nutt. sensu TJM2 (2012), in part] Mar–Jun [Online Interchange]

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Nov 25 2015
Citation for this treatment: [Author of taxon treatment] 2013. Crocanthemum, Revision 1, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Nov 25 2015

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Geographic subdivisions indicated for the distribution of Crocanthemum aldersonii Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.