BRITTON AND RO 



PLATE XV 



y 



i 



^ V.\T:t^..:..-. 



^- t:. Eaton del. 



1.2 



Parts of ioints of Opuntia exaltata 



3. Upper part of joint of Opuntia macrarthra. 



4. Upper part of joint of Opuntia iorhsptna. 



(All natural size.) 



