Peniocereus is a genus of vining cacti, comprising about 18 species, found from the southwestern United States and Mexico. They have a large underground tuber, thin and inconspicuous stems.Its name comes from the prefix penio- (from the Latin penis, meaning ‘tail’) and Cereus, the large genus from which it was split.[1]
Known as the desert night-blooming cereus, it also shares its common names of "night-blooming cereus" and "queen of the night" with many other similar cacti.
Peniocereus was first described in 1905 by Alwin Berger as a subgenus of Cereus with a single species, Cereus greggii. This taxon was elevated to the genus level as Peniocereus greggii by Britton and Rose in 1909. Later in 1974 an infrageneric classification was constructed based on morphological features that split Peniocereus into two subgenera: Peniocereus and Pseudoacanthocereus. In 2005 a molecular phylogenetic study of the genus supported this split and showed that Peniocereus is not monophyletic.[2]
Species include:[3]
Molecular phylogeny supported the position of this subgenus within Echinocereeae.
| Image | Scientific name | Distribution |
|---|---|---|
| Peniocereus greggii - desert nightblooming cereus | United States (Arizona, New Mexico, Texas), Mexico | |
| Peniocereus johnstonii | Mexico (Baja California Sur) | |
| Peniocereus lazaro-cardenasii | Mexico (Guerrero, Michoacan de Ocampo) | |
| Peniocereus viperinus | Mexico (Morelos, Puebla) | |
| Peniocereus zopilotensis | Mexico (Guerrero) | |
| Peniocereus marianus | Mexico (Sinaloa, Sonora) | |
| Peniocereus striatus - gearstem cactus | Mexico (Baja California, Sinaloa, and Sonora) and United States (Arizona) | |
The 2005 molecular study showed that P. serpentinus is in Echinocereeae along with subgenus Peniocereus, but suggests resurrecting the monotopic Nyctocereus as it is sister to Bergerocactus.
Molecular phylogeny and morphological evidence suggests this subgenus is more closely related to Acanthocereus.
| Image | Scientific name | Distribution |
|---|---|---|
| Peniocereus hirschtianus | Costa Rica, El Salvador, Guatemala, Nicaragua | |
| Peniocereus maculatus | Mexico (Guerrero) | |
| Peniocereus oaxacensis | Mexico (Oaxaca) | |
| Peniocereus cuixmalensis | Mexico (Colima, Jalisco, Michoacan de Ocampo) | |
| Peniocereus fosterianus | Mexico (Chiapas, Colima, Guerrero, Oaxaca) | |
| Peniocereus castellae | Mexico (Colima, Jalisco, Michoacan de Ocampo) | |
| Peniocereus macdougallii | Mexico (Oaxaca) | |
| Peniocereus rosei | Mexico (Jalisco, Sinaloa) | |
| Peniocereus tepalcatepecanus | Mexico (Michoacan de Ocampo) | |