4. Phyllanthus caroliniensis Walter, Fl. Carol. 228. 1788.
Carolina leafflower Carolina leafflower
Herbs, annual or perennial, without caudex or rhizomes, monoecious, 1–4.5 dm; branching not phyllanthoid. Stems terete, not winged [narrowly winged], glabrous or scabridulous. Leaves distichous; all well developed; stipules auriculate, pale brown or reddish brown; blade elliptic or oblong to obovate, 5–20(–30) × 2–10(–15) mm, base acute, apex obtuse to rounded and apiculate, both surfaces glabrous or scabridulous. Inflorescences cymules, bisexual, with 1–3(–5) pistillate flowers and 1–2 staminate flowers. Pedicels: staminate 0.5–1 mm, pistillate sharply reflexed in fruit, 0.5–1(–1.5) mm. Staminate flowers: sepals (5–)6, pale yellowish green, flat, 0.5–0.7 mm; nectary extrastaminal, 6 glands; stamens 3, filaments distinct. Pistillate flowers: sepals (5–)6(–7), green, often suffused with red, with scarious margins, flat, 0.6–1.4 mm, 1-veined; nectary cupular or annular, lobed or unlobed. Capsules 1.6–2 mm diam., smooth. Seeds uniformly brown, 0.7–1.1 mm, verrucose. 2n = 36 (subsp. guianensis, West Indies).
Subspecies 4 (2 in the flora): c, e United States, Mexico, West Indies, Central America, South America; introduced in se Asia.
Phyllanthus caroliniensis is the most widespread Phyllanthus in the flora area and in the Americas. In addition to the two subspecies in the flora, there are two others. Subspecies guianensis (Klotzsch) G. L. Webster, found in the West Indies, Central America, and northern South America, is similar to subsp. caroliniensis but distinguished by longer stipules (1.5–2 mm versus 0.8–12 mm) and staminate nectary glands that are longer than wide (versus as wide or wider than long). Subspecies stenopterus (Müller Arg.) G. L. Webster, of southern Central America and northern South America, is recognizable by its narrowly winged stems.