Herbs or subshrubs, annual [perennial]. Stems erect [creeping], unbranched or branched, glabrous [glabrate, scabrous, puberulent, or pilose]. Leaves sessile or petiolate; blade narrowly elliptic to elliptic, ovate, or suborbiculate, venation pinnate, surfaces sparsely appressed-hairy [pilose] or glabrous, scabrous or puberulent along margins and veins. Inflorescences terminal or axillary, dichasial, 20–100-flowered, each flower subtended by 1 bracetole. Flowers: sepals distinct or shortly connate at base, green centrally with whitish edges, ovate, deltate, or oblong; corolla usually white, sometimes mauve [violet], drying purple, urceolate, throat pilose or with ring of hairs; ovary superior; stigmas knoblike, 2-lobed. Fruits capsules, green, often drying purple, 2-valved, 2-horned, dehiscent along medial line. Seeds gold to dark brown, ellipsoid, obliquely ellipsoid, or depressed-subglobose [fusiform], reticulate or smooth [warty]. x = 10.

Distribution

c, se United States, Mexico, West Indies, Central America, n South America, s Asia (n India, Malaysia [Borneo]), w Africa, Indian Ocean Islands (Madagascar), n Australia.

Discussion

Species 8–10 (3 in the flora).

A. J. M. Leeuwenberg (1974) and J. B. Nelson (1980) gave thorough accounts of the nomen­clatural history of Mitreola and its synonymy.

Selected References

None.

Lower Taxa

Mitreola angustifolia, Mitreola petiolata, Mitreola sessilifolia

Key

1	Leaves petiolate or subsessile, blades 2–8 cm, base cuneate; inflorescences lax, flowers mostly shorter than internodes.	Mitreola petiolata
1	Leaves subsessile or sessile, blades (0.8–)1.2–3.3 cm, base usually rounded, sometimes cuneate; inflorescences congested, flowers longer than internodes.	> 2
2	Capsule horns papillose-warty over inner and outer faces; seeds smooth; larger leaves 1.5–2 times as long as wide.	Mitreola sessilifolia
2	Capsule horns lightly tuberculate mostly over inner faces; seeds reticulate; larger leaves 4–5 times as long as wide.	Mitreola angustifolia