Oenothera hartwegii

Oenothera hartwegii (syn. Calylophus hartwegii), Hartweg's sundrops, is a species of flowering plant in the evening primrose family Onagraceae. It is native to the desert southwest of the United States, and to northern and western Mexico. A perennial usually 30 to 45 cm tall and 60 cm wide, it is used locally as a drought-resistant ground cover.

Subtaxa
The following subspecies are accepted:
 * Oenothera hartwegii subsp. fendleri (A.Gray) W.L.Wagner & Hoch – Arizona, New Mexico, Kansas, Oklahoma, Texas, northeastern Mexico
 * Oenothera hartwegii subsp. filifolia (Eastw.) W.L.Wagner & Hoch – New Mexico, Texas, northeastern Mexico
 * Oenothera hartwegii subsp. hartwegii – Colorado, Texas, northern and western Mexico
 * Oenothera hartwegii subsp. maccartii (Shinners) W.L.Wagner & Hoch – Texas, northeastern Mexico
 * Oenothera hartwegii subsp. pubescens (A.Gray) W.L.Wagner & Hoch – Arizona, New Mexico, Colorado, Kansas, Oklahoma, Texas, northeastern Mexico