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Sonora croton, Sonoran croton

silver July croton

Habit Shrubs, 8–16 dm, monoecious. Herbs, annual, 2–12 dm, monoecious.
Stems

much-branched distally, canescent when young, becoming glabrate.

branching once into 2–3 branches, tomentose.

Leaves

sometimes clustered near inflorescences;

stipules subulate, to 1 mm;

petiole 0.4–1 cm, 1/4–1/2 leaf blade length, glands absent at apex;

blade ovate to broadly lanceolate, 0.8–4 × 0.6–2 cm, base cuneate to rounded or cordate, margins entire, not undulate, ciliate-glandular, apex acute to acuminate, abaxial surface pale green, sparsely whitish stellate-hairy, adaxial surface darker green, glabrate.

sometimes clustered near inflorescences;

stipules linear-subulate, 4–11 mm, unlobed or deeply divided;

petiole 0.3–8 cm, glands absent at apex;

blade ovate to ovate-oblong, 2–15 × 1.5–8 cm, base obtuse, cuneate, or subtruncate, margins denticulate, apex obtuse to rounded, abaxial surface pale green, not appearing brown-dotted, no stellate hairs with brown centers, densely stellate-hairy, adaxial surface green, less densely stellate-hairy.

Inflorescences

bisexual or staminate, racemes, 2–14 cm, staminate flowers 10–25, pistillate flowers 3–5(–8).

bisexual, congested racemes, 1–4 cm, staminate flowers 4–10, pistillate flowers 3–6.

Pedicels

staminate 1–1.5 mm, pistillate 1–4 mm.

staminate 2–3 mm, pistillate 1–4 mm (3–5 mm in fruit).

Staminate flowers

sepals 5, 1–1.5 mm, abaxial surface sparsely stellate-hairy;

petals 5, lanceolate, 1.5–2 mm, abaxial surface glabrous except margins villous;

stamens 13–16.

sepals 5, 1.5–2 mm, abaxial surface stellate-hairy;

petals 5, oblong, 2–3 mm, abaxial surface glabrous except margins ciliate;

stamens 10–13.

Pistillate flowers

sepals 5, equal, 1.5–2 mm, margins entire, apex incurved, abaxial surface sparsely stellate-hairy;

petals papillae, 0.5 mm;

ovary 3-locular;

styles 3, 2–3 mm, 2-fid, terminal segments 6.

sepals 5, unequal, 4–8 mm, margins deeply laciniate, apex incurved, abaxial surface stellate-hairy;

petals 0;

ovary 3-locular;

styles 3, 2–3 mm, 4-fid, terminal segments 12.

Capsules

7–8 × 5–6 mm, smooth;

columella apex with 3 rounded, inflated lobes.

5 × 7 mm, smooth;

columella 3-angled.

Seeds

6–7 × 3–4 mm, shiny.

3.2–3.8 × 2.4–3 mm, dull.

Croton sonorae

Croton argenteus

Phenology Flowering Jul–Sep. Flowering Jun–Dec.
Habitat Rocky slopes, desert scrub. Disturbed sites, waste areas, levees.
Elevation 500–1100 m. (1600–3600 ft.) 0–50 m. (0–200 ft.)
Distribution
from FNA
AZ; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
TX; e Mexico; Central America; South America; West Indies [Introduced in North America]
[BONAP county map]
Discussion

Croton sonorae is widely distributed in Mexico and extends into southern Arizona in Maricopa, Pima, and Pinal counties.

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

Croton argenteus, which in the flora area is known only from Cameron and Hidalgo counties, may be a fairly recent introduction into the United States; the earliest known collections date from 1923.

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

Source FNA vol. 12, p. 223. FNA vol. 12, p. 211.
Parent taxa Euphorbiaceae > Croton Euphorbiaceae > Croton
Sibling taxa
C. alabamensis, C. argenteus, C. argyranthemus, C. californicus, C. capitatus, C. ciliatoglandulifer, C. cortesianus, C. coryi, C. dioicus, C. elliottii, C. fruticulosus, C. glandulosus, C. heptalon, C. humilis, C. incanus, C. leucophyllus, C. lindheimeri, C. lindheimerianus, C. linearis, C. michauxii, C. monanthogynus, C. parksii, C. pottsii, C. punctatus, C. sancti-lazari, C. setigerus, C. soliman, C. suaveolens, C. texensis, C. wigginsii
C. alabamensis, C. argyranthemus, C. californicus, C. capitatus, C. ciliatoglandulifer, C. cortesianus, C. coryi, C. dioicus, C. elliottii, C. fruticulosus, C. glandulosus, C. heptalon, C. humilis, C. incanus, C. leucophyllus, C. lindheimeri, C. lindheimerianus, C. linearis, C. michauxii, C. monanthogynus, C. parksii, C. pottsii, C. punctatus, C. sancti-lazari, C. setigerus, C. soliman, C. sonorae, C. suaveolens, C. texensis, C. wigginsii
Synonyms C. attenuatus, C. pringlei family euphorbiaceae Julocroton argenteus
Name authority Torrey: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 194. (1859) Linnaeus: Sp. Pl. 2: 1004. (1753) — (as argenteum)
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