Strophocactus

Life-forms

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Ordo: Caryophyllales

Familia: Cactaceae
Subfamilia: Cactoideae
Tribus: Phyllocacteae
Subtribus: Echinocereinae
Genus: Strophocactus
Species: S. chontalensis – S. testudo – S. wittii
Name

Strophocactus Britton & Rose, Contr. U.S. Natl. Herb. 16: 262, pl. 84 (1913).

Type species: Strophocactus wittii (K.Schum.) Britton & Rose

Synonyms

Homotypic
Cereus [infragen.unranked] Foliosi K.Schum., Gesamtb. Kakt. Nachträge 1898 bis 1902: 50 (1903), nom. inval.
Cereus subsect. Phyllocereus A.Berger, Rep. (Annual) Missouri Bot. Gard. 16: 78 (1905).
Selenicereus sect. Strophocactus (Britton & Rose) D.R.Hunt, Bradleya 7: 93 (1989).
Strophocereus Frič & Kreuz., Verzeichnis Amer. Sukk. Rev. Syst. Kakteen 21 (1935), nom. illeg.

Heterotypic
Cereus [infragen.unranked] Divaricati K.Schum., Gesamtb. Kakt. (1): 56 (1897).
Cereus [infragen.gruppe] Testudines Vaupel in Engl. & Prantl, Nat. Pflanzenfam. 21: 637, 639 (1925).
Deamia Britton & Rose, Cactaceae 2: 212 (1920).
Cereus subg. Deamia (Britton & Rose) A.Berger, Kakteen: 6: 117 (1929).
Selenicereus sect. Deamia (Britton & Rose) D.R.Hunt, Bradleya 7: 93 (1989).
Type species: Cereus testudo Karw.

References

Britton, N.L. & Rose, J.N. 1913. Contr. U.S. Natl. Herb. 16: 262.
Tropicos
International Plant Names Index (IPNI)

Vernacular names
svenska: Sköldpaddskaktussläktet

Strophocactus is a genus of cacti in the subfamily Cactoideae.[2] Its status and circumscription remain somewhat uncertain, with the genus containing one to three species (not always the same ones). Molecular phylogenetic data suggest that it consists of three species, including two formerly comprising the genus Pseudoacanthocereus. With this circumscription, the species have different growth habits, but share similarities in their flowers, which are white and open at night.

Description

As circumscribed by Korotkova et al. in 2017, the three species of Strophocactus have tubular to funnel-shaped flowers with tubercules arranged in ribs and areoles with bristles. The flowers are white and open at night. They are followed by yellow to brown fruits. Two species (S. brasiliensis and S. sicariguensis) are scrambling or decumbent shrubs, with thin stems (up to 4.5 cm across) and tuberous roots. S. sicariguensis sometimes has flattened stem segments. The third species, S. wittii, is an epiphyte with flattened stems that cling to the trunks of trees using aerial roots.[2][3]
Taxonomy

The genus was erected by Nathaniel L. Britton & Joseph N. Rose in 1913 with only one species, Strophocactus wittii.[1][4] In 1989, David Hunt reduced Stophocactus to a section of the genus Selenicereus, Selenicereus sect. Strophocactus,[1] so that the species became Selenicereus wittii. In 2003, Ralf Bauer proposed restoring the genus Strophocactus, adding two further species (S. chontalensis and S. testudo). He excluded Stophocactus from the Hylocereeae.[5] Bauer's actions were based on unpublished DNA sequence data. A molecular phylogenetic study of the Hylocereeae in 2017 showed that in neither Hunt's nor Bauer's approach were Strophocactus and Selinicereus monophyletic:[2]
 
 

	Clade including Selinicereus wittii = Strophocactus wittii       Clade including Strophocactus chontalensis and Strophocactus testudo     Re-circumscribed tribe Hylocereeae, including Selenicereus species

 
 
 

Selenicereus wittii formed a clade with two species then placed in Pseudoacanthocereus:[2]
 
 

	Neoraimondia herzogiana       Pseudoacanthocereus brasiliensis       Pseudoacanthocereus sicariguensis      Selenicereus wittii     Strophocactus sensu Korotkova et al. (2017)[2]

 
 

Accordingly, the authors followed Bauer in placing Selenicereus wittii back in Strophocactus, but now together with the two former Pseudoacanthocereus species. Like Bauer, they excluded the revised genus Strophocactus from the Hylocereeae, placing it in the tribe Echinocereeae.[2]
Species

According to Korotkova et al. in 2017, the genus has three species:[2]

Strophocactus brasiliensis (Britton & Rose) S.Arias & N.Korotkova, syn. Pseudoacanthocereus brasiliensis (Britton & Rose) F. Ritter – Brazil
Strophocactus sicariguensis (Croizat & Tamayo) S.Arias & N.Korotkova, syn. Pseudoacanthocereus sicariguensis (Croizat & Tamayo) N.P.Taylor – Colombia, Venezuela
Strophocactus wittii (K.Schumann) Britton & Rose, syn. Selenicereus wittii (K.Schumann) Rowley – North Brazil, Colombia, Ecuador, Peru, Venezuela

Species formerly included in Strophocactus are:[2]

Strophocactus chontalensis (Alexander) Ralf Bauer = Deamia chontalensis (Alexander) Doweld
Strophocactus testudo (Karw. ex Zucc.) Buxb. ex Krainz = Deamia testudo (Karw. ex Zucc.) Britton & Rose

References

"Strophocactus Britton & Rose", The International Plant Names Index, retrieved 2021-02-23
Korotkova, Nadja; Borsch, Thomas & Arias, Salvador (2017), "A phylogenetic framework for the Hylocereeae (Cactaceae) and implications for the circumscription of the genera" (PDF), Phytotaxa, 327 (1): 1–46, doi:10.11646/phytotaxa.327.1.1
Anderson, Edward F. (2001), "Pseudoacanthocereus", The Cactus Family, Pentland, Oregon: Timber Press, pp. 591–592, ISBN 978-0-88192-498-5
"Strophocactus wittii Britton & Rose", The International Plant Names Index, retrieved 2021-02-23
Bauer, Ralf (2003), "A synopsis of the tribe Hylocereeae F. Buxb.", Cactaceae Systematics Initiatives, 17: 3–63, cited in Korotkova, Borsch & Arias (2017)