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common three-seed-Mercury, rhombic copper-leaf, rhombic or common threeseed Mercury, ricinelle rhomboïde

bastard copperleaf, Everglades copperleaf

Habit Herbs, annual, 1.5–6 dm, monoecious. Herbs, perennial, 1–2.5 dm, monoecious.
Stems

usually erect, sometimes ascending, usually sparsely pubescent, rarely sparsely hirsute.

prostrate to ascending, pubescent.

Leaves

petiole 0.4–7 cm;

blade ovate to broadly rhombic, 2–9 × 0.8–5 cm, base obtuse, margins crenate to serrate, apex acute to acuminate.

petiole 0.1–0.5 cm;

blade ovate to orbiculate, 0.3–2.1 × 0.3–1.2 cm, base cordate or rounded, margins serrate-crenate, apex obtuse or acute.

Inflorescences

bisexual, axillary;

peduncle 0.1–0.6 cm, pistillate portion 0.7–1.5(–2) × 1–2(–2.5) cm or pistillate bract solitary, staminate portion 0.3–1 cm;

allomorphic pistillate flowers rare, solitary in axils near base of stem.

bisexual, terminal;

peduncle 0.2–1 cm, pistillate portion 1.5–3 × 1–1.5 cm, staminate portion 0.8–2.5 cm;

allomorphic pistillate flowers absent.

Pedicels

of allomorphic flowers 1–2 mm.

Pistillate flowers

pistil 3-carpellate (normal flowers), 1-carpellate (allomorphic flowers);

styles multifid or laciniate.

pistil 3-carpellate;

styles multifid or laciniate.

Capsules

smooth, pubescent;

allomorphic fruits obovoid, 2 × 1 mm, spiny, pubescent.

smooth, pubescent.

Seeds

(1.2–)1.5–1.7(–2) mm, minutely pitted.

1.2–1.4 mm, minutely pitted.

Pistillate

bracts (normal flowers) loosely arranged to crowded (inflorescence axis clearly to scarcely visible between bracts) or solitary, 6–15 × 9–23 mm, abaxial surface sparsely pubescent and stipitate-glandular;

lobes (5–)7–9(–11), lanceolate to triangular, 1/3–2/3 bract length;

bracts of allomorphic flowers absent.

bracts crowded (inflorescence axis not or sparingly visible between bracts), 4–6 × 7–10 mm, abaxial surface pubescent and sessile-glandular;

lobes (7–)10–13, deltate to triangular, 1/5 bract length.

Acalypha rhomboidea

Acalypha chamaedrifolia

Phenology Flowering and fruiting summer–fall. Flowering and fruiting year-round, mainly spring–fall.
Habitat Deciduous and evergreen woods, moist depressions, swampy areas, riverbanks, agricultural fields, disturbed areas. Rocky pine woods, disturbed areas.
Elevation 0–1500 m. (0–4900 ft.) 0–10 m. (0–0 ft.)
Distribution
from FNA
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; NB; NS; ON; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
FL; West Indies
[BONAP county map]
Discussion

Acalypha rhomboidea often has been called A. virginica due to controversy about the typification of that name. Conservation of the type of A. virginica resolved the issue. This nomenclatural problem, combined with use of inappropriate characters to distinguish A. rhomboidea and A. virginica, has resulted in considerable confusion between these amply distinct species. The two can be distinguished most readily by the pistillate bracts, which are clearly hirsute abaxially in A. virginica but sparsely pubescent abaxially in A. rhomboidea. In addition, the bracts of A. virginica have (8–)10–14(–16) triangular lobes one fourth to one half the bract length, whereas those of A. rhomboidea have (5–)7–9(–11) lanceolate or triangular lobes one third to two thirds the bract length, and the stems of A. virginica usually are hirsute whereas the stems of A. rhomboidea are rarely so.

In the southern part of its range, many Acalypha rhomboidea plants have been confused with A. gracilens. These plants are more delicate than A. rhomboidea from farther north, with notably smaller pistillate bracts, and they usually produce allomorphic flowers, whereas more robust or northerly plants rarely do. They can be distinguished from A. gracilens by having relatively wider leaves and pistillate bracts with fewer lobes and no red sessile glands.

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

In the flora area, Acalypa chamaedrifolia is native to Miami-Dade and Monroe counties but has been sparingly, and apparently accidentally, introduced farther north.

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

Source FNA vol. 12, p. 170. FNA vol. 12, p. 166.
Parent taxa Euphorbiaceae > Acalypha Euphorbiaceae > Acalypha
Sibling taxa
A. alopecuroidea, A. arvensis, A. australis, A. californica, A. chamaedrifolia, A. deamii, A. gracilens, A. monococca, A. monostachya, A. neomexicana, A. ostryifolia, A. phleoides, A. poiretii, A. radians, A. setosa, A. virginica, A. wilkesiana
A. alopecuroidea, A. arvensis, A. australis, A. californica, A. deamii, A. gracilens, A. monococca, A. monostachya, A. neomexicana, A. ostryifolia, A. phleoides, A. poiretii, A. radians, A. rhomboidea, A. setosa, A. virginica, A. wilkesiana
Synonyms A. virginica var. rhomboidea Croton chamaedryfolius
Name authority Rafinesque: New Fl. 1: 45. (1836) (Lamarck) Müller Arg.: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 879. (1866)
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