CACTALES. 741 



Alliance LIT. CACTALES. — The Cactal Alliance. 



Diagnosis. — Epigynous Exogens, with dichlamydeous polypetalous foicers, parutal 

 placentcB, and an embryo with little or no alhumen. 



Their parietal placentation separates Cactals from all Epigjiious Orders except the 

 Grossal, and the latter is knoNV-n by the minute embryo and copious firm albumen. 



The Orders at first sight appear very different : but if we omit from consideration 

 the succulence of Indian Figs, their dissimilarity disappears. For Bartonia among 

 Loasads is much like an Epiphyllum in its flowers, and the difference between Homalium 

 and Mentzelia or Acrolasia is inconsiderable. In fact, the glands on the calyx of 

 Homaliads may be regarded as another form of the secondary petals of some Loasads. 



The AlUance touches Cucm'bits by way of such Loasads as Blumenbachia, Onagi'ads 

 through Bartonia, Ficoids (Mesembryacese) through Indian Figs, and Passionflowers 

 through such plants as the HomaUad Blackwellia. 



Natural Orders of Cactals. 



Sepals and petals distinct. Stamens opposite the petals. '^^2'^^l284. Homaliace^e. 



separate. Ovides pendulous J 



Sepals and petals distinct. Stamens scattered. Styles confluent. \2^^ Loasace^ 



Ovules pendidom. Seeds albuminoids J " ' 



Sepals and petals tmmerous, undistingzdshable. Stamens scattered. \cgQ Cactacee 



Styles confluent. Ovules horizontal. Seeds without albumen . . j " ' 



