Peniocereus

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.

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.

Taxonomy

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.

Species

Species include:

Peniocereus sensu stricto

Molecular phylogeny supported the position of this subgenus within Echinocereeae.

Image	Scientific name	Distribution
File:Peniocereus greggii var. greggii - Flickr - aspidoscelis (48).jpg	Peniocereus greggii(Engelm.) Britton & Rose	United States (Arizona, New Mexico, Texas), Mexico
	Peniocereus johnstoniiBritton & Rose	Mexico (Baja California Sur)
	Peniocereus lazaro-cardenasii(J.L.Contr., J.Jiménez Ram., Sánchez-Mej. & C.A.Toledo) D.R.Hunt	Mexico (Guerrero, Michoacan de Ocampo)
	Peniocereus marianus(Gentry) Sánchez-Mej.	Mexico (Sinaloa, Sonora)
	Peniocereus papillosus (Britton & Rose) U.Guzmán	Sinaola
	Peniocereus striatus – gearstem cactus	Mexico (Baja California, Sinaloa, and Sonora) and United States (Arizona)
File:Peniocereus viperinus.jpg	Peniocereus viperinus	Mexico (Morelos, Puebla)
	Peniocereus zopilotensis	Mexico (Guerrero)

Formerly included species

Nyctocereus

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.

Image	Scientific name	Distribution	Former name
File:Peniocereus serpentinus2126111279.jpg	Nyctocereus serpentinus	Mexico (Michoacan de Ocampo, Morelos, Oaxaca)	Peniocereus sepentianus

Subgenus Pseudoacanthocereus (Now Acanthocereus)

Molecular phylogeny and morphological evidence suggests this subgenus is more closely related to Acanthocereus.

Image	Scientific name	Distribution	Former name
	Acanthocereus castellae	Mexico (Colima, Jalisco, Michoacan de Ocampo)	Peniocereus castellae
File:Peniocereus cuixmalensis 01 SSZ.jpg	Acanthocereus cuixmalensis	Mexico (Colima, Jalisco, Michoacan de Ocampo)	Peniocereus cuixmalensis
	Acanthocereus fosterianus	Mexico (Chiapas, Colima, Guerrero, Oaxaca)	Peniocereus fosterianus
	Acanthocereus hirschtianus	Costa Rica, El Salvador, Guatemala, Nicaragua	Peniocereus hirschtianus
	Acanthocereus macdougallii	Mexico (Oaxaca)	Peniocereus macdougallii
File:Caudexacanthocereusmaculatus.jpg	Acanthocereus maculatus	Mexico ( Guerrero)	Peniocereus maculatus
	Acanthocereus oaxacensis	Mexico (Oaxaca)	Peniocereus oaxacensis
	Acanthocereus rosei	Mexico (Jalisco, Sinaloa)	Peniocereus rosei
File:Peniocereus tepalcatepecanus plant.jpg	Acanthocereus tepalcatepecanus	Mexico (Michoacan de Ocampo)	Peniocereus tepalcatepecanus

References

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