Flora of North America species comparison

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Croton heptalon

Croton incanus

woolly croton

salvia, Torrey's croton, vara blanca
Habit Herbs, annual, 5–15 dm, monoecious; stems, leaves, and buds whitish-hairy when young, becoming glabrate. Shrubs, 10–20 dm, monoecious.
Stems

well branched distally, stellate-hairy.

much branched distally, stellate-velutinous.
Leaves

not clustered;

stipules linear, 2–7 mm;

petiole 0.5–5 cm, glands absent at apex;

blade ovate-lanceolate, 3–10 × 1–5 cm, base cordate to rounded, margins entire, apex acute, abaxial surface pale green, not appearing brown-dotted, no stellate hairs with brown centers, adaxial surface darker green, both stellate-hairy.

sometimes clustered near inflorescences;

stipules linear-subulate, 2–3 mm;

petiole 0.7–1.5 cm, (1/4–)3/8–1/2 leaf blade length, glands absent at apex;

blade oblong, ovate-oblong, or elliptic-oblong, 1.5–4(–6) × 1.5–3 cm, base rounded to obtuse, margins entire, apex acute to obtuse, abaxial surface whitish, densely stellate-tomentose, adaxial surface darker green, stellate-tomentose.
Inflorescences

bisexual, racemes, 2–4 cm, staminate flowers 3–10, pistillate flowers 4–8.

bisexual, racemes, 2–5 cm, staminate flowers 10–25, pistillate flowers 2–4.
Pedicels

staminate 2–4 mm, pistillate 1–2 mm.

staminate 1.7–3 mm, pistillate 1–2 mm.
Staminate flowers

sepals (4–)5, 1–2 mm, abaxial surface stellate-hairy;

petals 5, linear-oblong-lanceolate, 1–1.5 mm, abaxial surface stellate-hairy;

stamens 9–12.

sepals 5, 1.5–2 mm, abaxial surface densely tomentose;

petals 5, oblanceolate, 1.5–2 mm, abaxial surface villous;

stamens 10–16.
Pistillate flowers

sepals 7–8, subequal, 3–6 mm, margins entire, apex straight to slightly incurved, abaxial surface whitish appressed-tomentose;

petals 0;

ovary 3-locular;

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

sepals 5, equal, 1.2–3.5 mm, margins entire, apex straight to slightly incurved, abaxial surface tomentose;

petals 0;

ovary 3-locular;

styles 3, 1.8–3.5 mm, 2-fid to base, terminal segments 6.
Capsules

6–8 × 6–7 mm, smooth;

columella tipped with 3-pronged grappling hooklike appendage.

6–8 × 4–5 mm, smooth;

columella apex with 3 rounded, inflated lobes.
Seeds

4–5 × 2–2.5 mm, shiny.

4.5–7 × 3–4 mm, dull.
2n

= 20.

Croton heptalon

Croton incanus
Phenology Flowering May–Dec. Flowering Mar–Nov.
Habitat Beaches, coastal dunes, roadsides. Calcareous loams, xeric rocky limestone slopes and canyons.
Elevation 0–50 m. (0–200 ft.) 0–700 m. (0–2300 ft.)
Distribution
from FNA
TX; e Mexico
[BONAP county map]
from FNA
TX; n Mexico; c Mexico
[BONAP county map]
Discussion

Morphological differences among Croton heptalon and its multifid-styled relatives in sect. Heptallon, especially C. capitatus and C. lindheimeri, can be quite subtle. In general, C. heptalon can be distinguished from C. capitatus by its more elongate pistillate part of the inflorescence, non-recurving sepal tips in the pistillate flowers, and more cordate leaf bases on larger basal leaves. Whitish pubescence on its young growth and styles that branch once into four terminal segments distinguish C. heptalon from C. lindheimeri.

Croton muelleri J. M. Coulter, which is an illegitimate name, pertains here.

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

Croton incanus is known in the flora area from the trans-Pecos region to south Texas.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 217. FNA vol. 12, p. 217.
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. 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
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. 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 Oxydectes heptalon, C. albinoides, C. capitatus var. albinoides, C. engelmannii var. albinoides, C. muelleri var. albinoides, Heptallon aromaticum C. suaveolens var. oblongifolius, C. torreyanus
Name authority (Kuntze) B. W. van Ee & P. E. Berry: Syst. Bot. 35: 159. (2010) Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 2(fol.): 58; 2(qto.): 73. (1817)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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