Iresine

Herbs, shrubs or vines, annual or perennial, polygamous or dioecious. Stems erect to prostrate, often trailing. Leaves opposite or alternate, petiolate; blade elliptic, ovate, or lanceolate to lance-oblong, margins entire or serrulate, glabrous or pubescent. Inflorescences terminal, diffuse, open panicles of spikes and axillary spikes; bracts and bracteoles membranous. Flowers unisexual; tepals 5, basally connate or distinct, 1–3-veined; stamens mostly 5; filaments connate basally; anthers 2-locular; pseudostaminodes absent or short; ovule 1; style 1, ca. 0.2 mm; stigmas 2–3, slender or capitate. Utricles globose, membranous, dehiscing irregularly. Seeds 1, dark red or reddish-brown, lenticular. x = 15.

Distribution

Mostly littoral in tropical and subtropical America (including Galápagos Islands), Asia (s Japan), and w Africa.

Discussion

Species ca. 70 (5 in the flora).

Selected References

Henrickson, J. and S. D. Sundberg. 1986. On the submersion of Dicraurus into Iresine (Amaranthaceae). Aliso 11: 355–364.

Lower Taxa

Iresine diffusa, Iresine heterophylla, Iresine leptoclada, Iresine palmeri, Iresine rhizomatosa

Key

1	Leaves alternate	Iresine leptoclada
1	Leaves opposite	> 2
2	Stems woody nearly throughout; tepals of pistillate flowers ± equaling bractlets	Iresine palmeri
2	Stems herbaceous; tepals of pistillate flowers longer than bractlets	> 3
3	Plants annual or weakly perennial, 4-30 dm; tepals 0.6-0.8 mm, apex obtuse or rounded	Iresine diffusa
3	Plants perennial, 3-10 dm; tepals 1-1.3 mm, apex acute to acuminate	> 4
4	Leaf blades 6-15 cm; tepals of pistillate flowers shorter than utricle	Iresine rhizomatosa
4	Leaf blades 3-6 cm; tepals of pistillate flowers longer than utricle	Iresine heterophylla