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Published In: Species Plantarum 2: 1003. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Acceptance : Accepted
Project Data     (Last Modified On 7/23/2009)


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1. Acalypha L. (three-seeded mercury)

Plants annual (perennial herbs, shrubs, or trees elsewhere), monoecious (dioecious elsewhere), taprooted, with clear sap, pubescent with unbranched, nonglandular and sometimes also gland-tipped hairs; stinging hairs absent. Stems erect, branched or unbranched. Leaves alternate, short- to long-petiolate, the petiole attached at the base of the nonpeltate blade. Leaf blades variously shaped, angled or rounded at the base, angled or tapered to a usually sharply pointed tip, the margins entire or more commonly toothed, often more or less with 3 main veins from the base. Stipules scalelike, 0.5–1.5 mm long, tan to purple or sometimes green, usually shed early, linear to narrowly triangular, often with few to several bristly hairs at the tip. Inflorescences axillary and sometimes also terminal, usually associated with longitudinally folded or concave, persistent, lobed, leaflike bracts, the basic units small clusters of staminate or pistillate flowers, these arranged into spikes or racemes, the pistillate clusters either basal to the staminate clusters in the same spike or in separate terminal spikes. Flowers lacking a corolla and nectar disc. Staminate flowers sessile or nearly so, minute (less than 0.5 mm long), with 4 linear to narrowly triangular sepals (these hairy) and 4–8 minute stamens having short filaments (these free or fused at the very base). Pistillate flowers with 3(–5) minute, linear to ovate sepals, the ovary with 1, 2, or more commonly 3 locules and 1 ovule per locule, the 3 styles separate or fused only at the very base, each irregularly pinnately divided into several slender lobes. Fruits 2- or 3-lobed (except in A. monococca). Seeds ovoid, with a flattened, oblong to narrowly elliptic, small, white caruncle (or this apparently absent), the surface otherwise nearly smooth to shallowly pitted or with small tubercles, dark brown to light gray or tan, sometimes mottled. About 450 species, North America to South America, Caribbean Islands, Africa, Asia to Australia, Pacific Islands; introduced in Europe.

The large genus Acalypha is most diverse in the American tropics. Several species are cultivated as houseplants (and outdoors in warmer regions) for their foliage or inflorescences, especially the paleotropical shrub A. hispida Burm. f. (chenille plant, red-hot cattail), which has elongate pistillate spikes whose fuzzy texture and red coloration is caused by the feathery-branched, red styles.


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1.1. Pistillate flowers in separate elongate terminal spikes, the staminate spikes axillary; at least some of the leaf blades shallowly cordate at the base, the margins with numerous (18–36 on each side) closely spaced teeth ... 4. A. OSTRYIFOLIA

Acalypha ostryifolia
2.1. Spikes all axillary, all or mostly with 1–3 basal pistillate flowers below the short to elongate portion with several to numerous staminate flowers; none of the leaf blades cordate, all tapered to broadly angled or slightly rounded at the base, the margins entire or more commonly with few to several (2–15 on each side) often broadly spaced teeth

3.2. Bracts 5–9(–11)-lobed; leaves long-petiolate, the petiole slightly shorter than to slightly longer than the blade

4.3. Fruits 2-locular, 2-seeded; seeds 2.2–3.2 mm long ... 1. A. DEAMII

Acalypha deamii
5.3. Fruits 3-locular, usually 3-seeded (rarely 1 of the ovules aborting); seeds 1.3–2.0 mm long ... 5. A. RHOMBOIDEA

Acalypha rhomboidea
6.2. Bracts (9–)10–17-lobed; leaves relatively short-petiolate, the petiole 1/16–1/2 as long as the blade

7.4. Leaves with the petiole 1/4–1/2 as long as the blade, mostly longer than the inflorescence bract(s) at the same node; bracts with the lobes triangular-ovate to broadly oblong, usually lacking stalked and sessile glands (rarely sparse glands present) ... 6. A. VIRGINICA

Acalypha virginica
8.4. Leaves with the petiole 1/16–1/4 the length of the blade, mostly shorter than to occasionally about as long as the inflorescence bract(s) at the same node; bracts with the lobes linear to lanceolate, narrowly oblong, or triangular-ovate, usually with at least some of the pubescence of white-stalked and/or red sessile glands

9.5. Fruits 3-locular, usually 3-seeded (rarely 1 of the ovules aborting); leaf blades narrowly lanceolate to more commonly oblong-lanceolate, oblong, or narrowly ovate; inflorescence bracts with the lobes mostly linear to lanceolate or narrowly oblong ... 2. A. GRACILENS

Acalypha gracilens
10.5. Fruits 1-locular, 1-seeded; leaf blades linear to lanceolate; inflorescence bracts with the lobes mostly lanceolate to triangular-ovate ... 3. A. MONOCOCCA
Acalypha monococca