Phytologia (A ug 2004) 86(2) 5 9 



noted "Zu alien iibrigen Triben konnen keine Beziehungen erkannt 

 werden." The earliest valid subfamilial name applicable to the sister 

 clade of columnar, epiphytic and South American globular cacti appears 

 to be Rhipsalidoideae Burnett. The Rhipsalidoideae as recognized here 

 includes all members of tribes Rhipsalideae DC, Echinocereae (Br. 

 & Rose) Buxb., Hylocereae (Br. & Rose) Buxb., Cereae Salm-Dyck, 

 Pachycereae Buxb., Trichocereae Buxb., Browningieae Buxb. and, with 

 the exclusion of Blossfeldia, Notocacteae Buxb. 



The Cactaceae has been notorious for parallel evolution in 

 morphology that thwarts phylogenetic classification. Parallel reduction 

 in shoot, leaf, flower and seed development in multiple phylogenetic 

 lineages was described by Buxbaum (1951, 1956 and 1965) following 

 phylogenetic ideas of Berger (1926). Although abundant molecular 

 synapomorphies distinguish the Cactoideae and Rhipsalidoideae, unique 

 morphological synapomorphies uniting each clade are difficult to identify. 

 A key to the six subfamilies recognized on the basis of morphological 

 discontinuities and DNA evidence is provided below. 



KEY TO THE SUBFAMILIES OF CACTACEAE 



la. Areoles bearing glochids, seeds large, alveolate; 

 bony aril covering the entire seed Opuntioideae 



lb. Areoles without glochids, seeds small, usually 

 exarillate or only the hilum covered by a strophiole 

 or corky strophiolar pad. 



2a. Plants with persistent photosynthetic leaves on stems. 



3a. Plants tree-like or shrubs with laminar leaves... Pereskioideae 



3b. Plants low caespitose shrubs with terete leaves 



Maihuenioideae 



2b. Plants without persistent photosynthetic leaves on stems. 



