FNA: Phyllanthus abnormis vs. Phyllanthus

Distribution

FL; NM; OK; TX; ne Mexico

North America; Mexico; Central America; South America; West Indies; Asia; Africa; Indian Ocean Islands; Pacific Islands; Australia; primarily tropical and subtropical regions [Introduced in Bermuda, Atlantic Islands, (Macaronesia)]

[BONAP county map]

Discussion

Varieties 2 (2 in the flora).

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

Species 800–850 (16 in the flora).

Phyllanthus is by far the largest genus in Phyllanthaceae and shows tremendous diversity in habit, from trees to small annual herbs, including a floating aquatic herb. Most species exhibit phyllanthoid branching (G. L. Webster 1956–1958), with well-developed leaves and flowers produced only on the ultimate branchlets, which in woody species are deciduous, and scalelike leaves on all other stems (referred to as main stems in this treatment; see family discussion for more details). Phylogenetic studies using DNA sequence data suggest that phyllanthoid branching evolved once and has been lost repeatedly, including within the clades containing P. caroliniensis and P. warnockii (H. Kathriarachchi et al. 2006). These studies also indicated that Phyllanthus is paraphyletic and that few of the subgenera and sections used by Webster (1956–1958, 1967) are monophyletic (K. Wurdack et al. 2004; Kathriarachchi et al. 2005, 2006; P. Hoffmann et al. 2006). However, it is premature to revise the classification of the genus (Kathriarachchi et al. 2006) and the sequence of species used here generally follows the classification by Webster (1956–1958, 1967, 1970). Exceptions are P. warnockii, which he treated as the sole member of Reverchonia but molecular phylogenetic studies show to be embedded in Phyllanthus (Kathriarachchi et al. 2006), and P. fluitans, which he did not treat; the latter species appears to be closely related to P. caroliniensis (Kathriarachchi et al. 2006).

A number of Phyllanthus species are of economic importance. Some cladode-producing species, especially P. angustifolius and P. epiphyllanthus Linnaeus, are grown as ornamental shrubs in tropical and subtropical areas (and in hothouses elsewhere); the former species has become sparingly naturalized in south Florida. Otaheite (or Tahitian) gooseberry tree, P. acidus, is grown throughout the tropics for its tart drupes; it has naturalized in south Florida. The floating aquatic herb P. fluitans (floating spurge or red root floater), is increasingly popular for use in tropical fish aquaria. Both P. amarus and P. urinaria have become weeds throughout tropical and subtropical areas, including the southeastern United States, and the American P. caroliniensis has become a weed in southeast Asia. Several annual species, notably P. niruri and P. urinaria, are widely used in folk medicine to treat a variety of ailments, especially urinary problems, and are now the subject of intense pharmacological research.

In Phyllanthus, taxa that are not consistently distinct morphologically but are geographically disjunct are recognized as subspecies (for example, P. caroliniensis subspp. caroliniensis and saxicola). Those that intergrade morphologically and geographically, as in P. abnormis, are treated as varieties.

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

Key

1. Pistillate nectary glands strongly unequal, spatulate, as long as or longer than broad; leaf blades glabrous on both surfaces or sparsely to moderately scabridulous abaxially; bisexual cymules with 1 staminate flower.	var. abnormis
1. Pistillate nectary glands subequal, reniform, broader than long; leaf blades densely scabridulous on both surfaces; bisexual cymules with 1–3 staminate flowers.	var. riograndensis

1. Floating aquatic herbs.	P. fluitans
1. Terrestrial herbs, shrubs, or trees.	→ 2
2. Branching not phyllanthoid; leaves all well developed.	→ 3
3. Leaves distichous; staminate sepals 0.5–0.7 mm.	→ 4
4. Stems terete, not winged; capsules 1.6–2 mm diam.; seeds 0.7–1.1 mm.	P. caroliniensis
4. Stems proximally terete, distally compressed, winged; capsules 2.8–3.2 mm diam.; seeds 1.3–1.5 mm.	P. evanescens
3. Leaves spiral; staminate sepals 0.7–2.5 mm.	→ 5
5. Sepals dark reddish purple, medially incurved and distally spreading; stamens 2, filaments distinct; staminate nectary intrastaminal, annular, 4-lobed; capsules 7–9.8 mm diam.; seeds mottled, (4.4–)4.7–6.2(–6.6) mm.	P. warnockii
5. Sepals green, greenish yellow, or pale brown, sometimes suffused with red, flat; stamens 3, filaments connate 2/3+ length; staminate nectary extrastaminal, 6 glands; capsules 2–4 mm diam.; seeds uniformly colored, 0.9–1.8 mm.	→ 6
6. Shrubs; leaf blades 1.5–3.5(–5) × 0.7–1.5 mm, apices pungent; staminate pedicels 0.6–0.8 mm, pistillate 0.9–1.2 mm; capsules 2 mm diam.; seeds 0.9–1 mm.	P. ericoides
6. Perennial herbs; leaf blades 5–24 × 1.5–10 mm, apices rounded, mucronulate, or apiculate; staminate pedicels 1.5–3.5 mm, pistillate 2.5–8 mm; capsules 2.7–4 mm diam.; seeds (1.1–)1.2–1.8 mm.	→ 7
7. Herbs with woody caudices; leaf blades 5–10 × 1.5–5 mm; pistillate sepals 1.5–2.5 mm; capsules 2.7–3.2 mm diam.; seeds (1.1–)1.2–1.4(–1.5) mm.	P. polygonoides
7. Herbs with rhizomes; leaf blades 10–24 × 5–10 mm; pistillate sepals 2.8–3.5 mm; capsules 4 mm diam.; seeds 1.7–1.8 mm.	P. liebmannianus
2. Branching phyllanthoid; leaves on main stems scalelike, on ultimate branchlets well developed or scalelike.	→ 8
8. Shrubs or trees.	→ 9
9. Ultimate branchlets terete; leaves on ultimate branchlets well developed, deciduous with branchlets; fruits drupes.	P. acidus
9. Ultimate branchlets flat (cladodes); leaves on ultimate branchlets scalelike, caducous; fruits capsules.	P. angustifolius
8. Herbs.	→ 10
10. Stamens 5, filaments distinct; pistillate pedicels flexuous and pendent in fruit.	P. tenellus
10. Stamens 2–3, filaments connate; pistillate pedicels spreading in fruit.	→ 11
11. Leaf blade abaxial surfaces hispidulous near margins; staminate pedicels 0.1–0.2 mm, pistillate 0.3–0.5 mm; capsules ± tuberculate; seeds transversely ribbed.	P. urinaria
11. Leaf blade abaxial surfaces glabrous or scabridulous; staminate pedicels 0.2–1.8 mm, pistillate (1–)1.2–7 mm; capsules smooth; seeds verrucose or longitudinally ribbed.	→ 12
12. Pistillate sepals 3–3.5 mm, pinnately veined; staminate sepals 1.5–3 mm; seeds verrucose, 1.5–1.8 mm; capsules 3.5 mm diam.; pistillate nectary annular, unlobed.	P. niruri
12. Pistillate sepals (0.5–)0.7–1.5 mm, 1-veined or obscurely veined; staminate sepals 0.3–1 mm; seeds longitudinally ribbed, 0.8–1.5 mm; capsules 1.7–2.7 mm diam.; pistillate nectary 3 glands or annular and 5–9-lobed.	→ 13
13. Perennial herbs; stipules of main stems dark brown, auriculate; capsules 1.7–1.9 mm diam.; seeds 0.8–0.9 mm.	P. pentaphyllus
13. Annual herbs; stipules of main stems pale green to pale brown, not auriculate; capsules 1.9–2.7 mm diam.; seeds 0.9–1.5 mm.	→ 14
14. Ultimate branchlets narrowly winged, main stems angled; distal inflorescences of solitary pistillate flowers.	P. fraternus
14. Ultimate branchlets not winged, main stems terete; distal inflorescences of 1 pistillate flower and 1–3 staminate flowers.	→ 15
15. Pistillate nectary annular, 5–7-lobed; staminate sepals 5(–6); capsules 1.9–2.1 mm diam.; seeds 0.9–1 mm.	P. amarus
15. Pistillate nectary 3 glands; staminate sepals 5–6 in flowers of basal cymules, 4 in flowers of distal cymules; capsules 2.3–2.7 mm diam.; seeds 1.1–1.5 mm.	P. abnormis