CLASSIFICATION 27 



has hard prickles which can tear the flesh, while the 

 latter has soft prickles which cannot. But there are 

 many different kinds of blackberry, some of which 

 differ from one another in such small and variable 

 characters that even specialists who have spent a large 

 part of their lives in the study of the blackberries do 

 not agree as to exactly how they should be grouped. 



We distinguish the kinds or groups of individuals 

 which resemble one another more or less closely, and 

 which interbreed freely, as species, but authorities 

 differ as to what they consider species, and there is 

 not yet agreement as to whether the conception of a 

 species can be made at all a precise conception. Species 

 which are most like each other are grouped into genera, 

 and genera which are most like each other into families. 

 Thus the raspberry and the blackberry are different 

 species of one genus, the sweet briar and the dog rose 

 of another genus belonging to the same family. The 

 hare and the rabbit are different species of one genus ; 

 the dog, the wolf and the fox of another belonging to 

 quite a different family, though to the same large 

 group, the mammals, which include all animals that 

 suckle their young, comprising such diverse types as 

 rats and mice, elephants, whales and men. 



The conventional nomenclature, which is used in 

 naming the different species we recognise, and enables 

 us to record and systematise them, gives each genus 

 a Latin name a noun and adds a qualifying adjec- 

 tive for the species. Thus the genus to which both 

 the blackberry and raspberry belong is called Rubus, 

 the former (if we lump all the blackberries together as 

 one species) being Rubus fruticosus, the latter Rubus 

 idceus. The genus Rosa includes Rosa rubiginosa, the 

 sweet briar, and Rosa canina, the dog rose, as well 



