Gomphrena

Herbs, annual or perennial. Stems ascending, decumbent, prostrate, or erect. Leaves opposite, sessile or petiolate; blade ovate to obovate, not fleshy, margins entire, long-pilose abaxially and sometimes adaxially. Inflorescences terminal and/or axillary, sessile, subglobose heads, often subtended by involucres of sessile leaves; bracts and bracteoles thin. Flowers bisexual; tepals 5, connate proximally; stamens 5; filaments connate basally into tube; pseudostaminodes absent; ovule 1; style 1, 1.5–4 mm; stigmas 2(–3), subulate or filiform. Utricles included in tepals, stramineous, ovoid or oblong, somewhat compressed, membranous, usually indehiscent. Seeds 1, lenticular, subglobose, to ovoid, smooth.

Distribution

Tropical, subtropical, and warm-temperate regions.

Discussion

Species ca. 100 (9 in the flora).

Selected References

Holzhammer, E. 1955. Die amerikanischen Arten der Gattung Gomphrena Linné. I. Mitt. Bot. Staatssamml. München 2: 85–114.

Holzhammer, E. 1956. Die amerikanischen Arten der Gattung Gomphrena Linné. II. Mitt. Bot. Staatssamml. München 2: 178–257.

Lower Taxa

Gomphrena caespitosa, Gomphrena globosa, Gomphrena haageana, Gomphrena martiana, Gomphrena nealleyi, Gomphrena nitida, Gomphrena serrata, Gomphrena sonorae, Gomphrena viridis

Key

1	Bractlets not cristate	> 2
1	Bractlets cristate along keel	> 5
2	Plants cespitose 3-15 cm; stems with 1-2 pairs of leaves	> 3
2	Plants not cespitose, 4-60 cm; each stem bearing numerous leaves	> 4
3	Leaf blades green, very sparsely villose, glabrate; blades of cauline leaves longer than broad	Gomphrena viridis
3	Leaf blades gray, densely villose; blades of cauline leaves as broad as long	Gomphrena caespitosa
4	Flower tubes glabrous; inflorescence heads not subtended by 2 leaves	Gomphrena martiana
4	Flower tubes lanose proximally; inflorescence heads subtended by 2 leaves	Gomphrena sonorae
5	Roots fleshy, fusiform; plants perennial	> 6
5	Roots fibrous; plants annual or sometimes perennial (G. serrata)	> 7
6	Leaf blades 1.5-4 cm, apex rounded; perianth 4.5-4.7 mm	Gomphrena nealleyi
6	Leaf blades 3-10 cm, apex acute to acuminate; perianth ca. 5.3 mm	Gomphrena haageana
7	Inflorescence heads 20-28 mm diam	Gomphrena globosa
7	Inflorescence heads 8-16 mm diam	> 8
8	Bractlets with denticulate crests; inflorescence heads 9-13 mm diam., usually tinged with red or pink; stems usually decumbent	Gomphrena serrata
8	Bractlets with laciniate crests; inflorescence heads 12-16 mm diam, yellowish white, rarely reddish; stems usually erect	Gomphrena nitida