WAYSIDE WEEDS. 21 1 



Plants which have the corolla in one piece, repre- 

 sented by the primroses, dead nettles, etc. 



Plants in which both corolla and calyx are 

 resolved into one floral covering, represented by the 

 buckwheats, docks, etc. 



Again these groups have, as already pointed out, 

 their own subdivisions, dependent chiefly upon the 

 attachment of the stamens and pistil, tiU at length, 

 by tracing' other difierences, we reach the natural 

 families of plants so frequently alluded to, as the 

 Eanunculacese, Eosacese, Umbellifer^, etc. 



But a "natural family" is itself only a group of 

 other smaller groups, the number of the latter 

 varying greatly. Bach of the smaller groups is 

 known as a "genus,"* and, lastly, each genus is 

 but aa aggregation of individual plants, each of 

 which is called a species. For example, it may be 

 remembered that in our opening chapter, where the 

 ranunculus or buttercup genus is cited, mention 

 is also made of various kinds of buttercup, which, 

 although bearing an unmistakeable family likeness, 

 were yet found to offer minor differences, such as a 

 turned back calyx, a bulbous root, a farrowed, 

 peduncle, which marked them as essentially different 

 from each other. These, therefore, are different 

 kinds or " species" of the Eanunculus genus ; but 

 the Eanunculus genus, though representative of the 

 "natural family" of the Eanunculacese, also associates 

 with itself in that family a number of other genera, 



* Plural, "Genera." 



