Acalypha rhomboidea
Acalypha californica
common three-seed-Mercury, rhombic copper-leaf, rhombic or common threeseed Mercury, ricinelle rhomboïde
California acalypha, California copperleaf, heirba del cancer, Pringle threeseed Mercury
usually erect, sometimes ascending, usually sparsely pubescent, rarely sparsely hirsute.
erect, hirsute and stipitate-glandular, becoming glabrate.
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.
persistent or drought-deciduous;
petiole 0.5–2.5 cm;
blade ovate to cordate, 1–5 × 0.5–4 cm, base truncate to rounded or cordate, margins serrate-crenate, apex acute or obtuse.
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.
unisexual and bisexual, axillary and terminal;
staminate peduncle 0.3–2.5 cm, fertile portion 1–4 cm;
pistillate peduncle 0.4–3 cm, fertile portion 1–3 × 0.8–1.2 cm;
bisexual similar to staminate, with 1–3 pistillate bracts near base;
allomorphic pistillate flowers absent.
of allomorphic flowers 1–2 mm.
pistil 3-carpellate (normal flowers), 1-carpellate (allomorphic flowers);
styles multifid or laciniate.
pistil 3-carpellate;
styles multifid or laciniate.
smooth, pubescent;
allomorphic fruits obovoid, 2 × 1 mm, spiny, pubescent.
smooth, pubescent and stipitate-glandular.
(1.2–)1.5–1.7(–2) mm, minutely pitted.
1.5–2 mm, minutely pitted.
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 loosely arranged (inflorescence axis visible between bracts), 3–6 × 5.5–11 mm, abaxial surface pubescent, sessile- and stipitate-glandular;
lobes (8–)10–18, rounded, 1/5 bract length.
= 20.
Acalypha rhomboidea
Acalypha californica
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.)
Plants in Arizona and Sonora have been segregated as Acalypha pringlei based on having long nonglandular hairs mixed with shorter hairs on the stem (versus hairs all of one length). This trait appears throughout the range of A. californica and cannot be used to distinguish two species (G. A. Levin 1995).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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