60 Phytologia (Aug 2004) 86(2) 



4a. Stems virtually lacking stomata except in sunken 

 crypts; stems lacking thickened cuticle with epidermis 

 lacking thickened outer cell walls, lacking thickened 

 hypodermal layer, stem always flattened globular 

 or disciform less than 25mm diameter; round seeds 

 with strophiole nearly equal in size to the rest of the 

 seed Blossfeldioideae 



4b. Stems with stomata or if few then not restricted 

 to cylindrical crypts, usually with thickened cuticle, 

 an epidermal layer with outer cell walls thickened 

 and a hypodermal layer; stems variously fiat, triangular 

 globular or columnar; seeds not round, seeds usually 

 exarillate (except in Parodia, Strombocactus, and Aztekium). 



5a. Flowers with naked pericarpels, bearing neither 

 areoles nor scales. 



6a. Plants globular or short cylindrical, never tall 

 columnar, never with a cephalium, never epiphytic, 

 restricted to North America or the Caribbean; seeds 

 usually with disjunct hilum and micropyle Cactoideae 



6b. Plants with flat (Schlumbergera), triangular, 

 columnar (Pachycereus, Pilosocereus, Espostoopsis) 

 stems or epiphytic (Rhipsalis, Hatiora, Lepismium), 

 if globular then bearing a cephalium (Melocactus) or 

 restricted to South America (Uebelmannia, some 

 species of Matucana), seeds with conjunct 

 hilum-micropylar region Rhipsalidoideae 



5b. Flowers with pericarpels bearing scales and/or areoles. 



7a. Areoles on pericarpel felted, or with hairs, 

 bristles or spines Rhipsalidoideae 



