5. Petrogenia I. M. Johnston, J. Arnold Arbor. 22: 116. 1941.
[Greek petra, rock, and genes, born, alluding to habitat]
Daniel F. Austin†
Perennials or subshrubs. Stems decumbent, erect, prostrate, or trailing, sometimes rooting at nodes, mat-forming, sericeous. Leaves petiolate; blade elliptic to lance-elliptic, 6–14 mm, surfaces sericeous. Inflorescences: flowers solitary, subsessile. Flowers: sepals: outer ovate-lanceolate, 2.5–4(–6) mm, inner lanceolate-acuminate, 2.5–3(–5) mm; corolla greenish yellow to yellow, ± campanulate, 3–4 mm, limb 5-lobed; styles 2, distinct or connate from base to 1/2 length; stigmas globose. Fruits capsular, globose, dehiscence valvate. Seeds (1–)4, ellipsoid to trigonous, glabrous.
Species 1: Texas, n Mexico.
This treatment follows S. Stefanović et al. (2003), who recognized Petrogenia as a monospecific genus, whereas D. F. Austin and G. W. Staples (1985) synonymized it under Bonamia.
SELECTED REFERENCE Austin, D. F. and G. W. Staples. 1985. Petrogenia as a synonym of Bonamia (Convolvulaceae), with comments on allied species. Brittonia 37: 310–316.
