Phytologia (Aug 2004) 86(2) 53 



of Cactaceae (Nopalaceae) divided into subfamilies Rhipsalidoideae 

 (Rhipsalidae) including only the genus Rhipsalis Gaertner, and 

 Opuntioideae (Opuntidae) including the genera Mammillaria Haw., 

 Melocactus Link & Otto, Echinocactus Link & Otto, Cereus Mill., 

 Opuntia Mill., and Pereskia Mill. Engelmann's (1876) creation of 

 subfamily Pereskioideae (Peireskieae) and division of the family into 

 three subfamilies for the Botany of California begins the modem era in 

 cactus classification. Treating only a few genera Engelmann heralded the 

 classification in three subfamilies years ahead of Schumann (1890,1898) 

 whose Cactoideae (Cereoideae), Pereskioideae (Peireskioideae) and 

 Opuntioideae have been included in most subsequent taxonomic studies 

 (Berger 1926,1929; Backeberg 1958,1966; Buxbaum 1958, Barthlott and 

 Hunt 1993; but see also Britton and Rose 1919-1923; Hunt 1967; Benson 

 1982 for recognition of these same groups at tribal rank). Cactoideae 

 Eaton, Opuntioideae Burnett, and Pereskioideae Engelm. appear to 

 be validly published, and under the International Code of Botanical 

 Nomenclature (Greuter et al. 2000) these names take priority over the 

 subfamilial names authored by Karl Schumann. 



The Opuntioideae and Pereskioideae have been clearly 

 circumscribed and almost uniformly recognized in modern times, 

 discounting the uncertain placement of Maihuenia Schum, a genus 

 of only two species from the southern Andes and Patagonia. First 

 associated with the caespitose opuntias, Maihuenia was soon reassigned 

 to the Pereskioideae by Schumann (1898) based on spine, flower, 

 and seed characters. Gibson's (1977) interpretation of stem tissues 

 and pollen features supported this placement, however Bailey (1968) 

 excluded Maihuenia from the Pereskioideae based on stem and vascular 

 anatomy, and was also unwilling to place it with Opuntioideae based 

 on similar terete leaves. Bailey noted similarities of pollen and highly 

 modified wood that to him suggested a possible relationship with the 

 Cactoideae (Cereoideae). Later, the genus was raised to subfamilial rank 

 by Fearn (1996) who may have been spurred by provisional molecular 

 evidence (see Leuenberger 1997 p.58 and references within, Doweld 

 1999 p.25). With the exclusion of Maihuenia the monophyly of the 

 Pereskioideae, including only Pereskia Mill., has never been questioned 

 on morphological grounds. 



