4.5. Boerhavia gracillima Heimerl (1889: 81–87) .

Lectotype (designated by Standley 1911: 421):― MEXICO. Chihuahua, rocky hills near Chihuahua, 15 August 1885, Pringle 665 (WU0033299 [image!] image available at https://wu.jacq.org/ WU0033299; isolectotype GOET008279 [image!] image available at https://plants.jstor.org/stable/10.5555/al.ap.specimen.goet008279).

Distribution in Mexico: ― Boerhavia gracillima is reported from Aguascalientes, Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Guanajuato, Hidalgo, Jalisco, Michoacán, Nuevo León, Puebla, Querétaro, San Luis Potosí, Sonora, Sinaloa, Tamaulipas y Zacatecas (Sandoval-Ortega et al. 2020). In Sonora it is distributed in Sonora biogeographic province (Fig. 4B), and has been collected in Álamos, Cajeme, Cucurpe, Guaymas, Hermosillo, La Colorada, Onavas, Sahuaripa and Yécora municipalities, in xerophytic scrub, at 100–400 m a.s.l.