254 c^sii. 



Group Y. C^sii. 



Caules ssepissime arcuato-prostrati, teretes vel sub- 

 angulati, pruinosi. Aculei inaequales. Aciculi setae 

 pilique pauci vel nuUi. 



This is a very natural group of plants, and for that 

 reason very difficult to divide into its true species. The 

 limits of several of those which I have adopted are far from 

 being known with cei-tainty. 



Although these plants clearly belong to the glandular 

 section of the genus, the setae and aciculi are often very far 

 from abundant. They are usually difficult to detect upon 

 the stems of R. corylifoUua and R. Balfourianus, and those 

 plants might easily be supposed to form parts of the group 

 Villicaules, if they did not possess scattered and rather un- 

 equal prickles and more or less pruinose stems. 



