OEGANS OF KEPEODUCTION. 



45 



In St. John's wort, and some of the Australian myrtle 

 family, a number of filaments are united together at their 

 base in three or more bundles surrounding the pistil. 

 In the Composite family, the anthers are linear and 

 united by their edges, forming a tube, while their fila- 

 ments are free (fig. 4, a). These four modes of union 

 characterize the sixteenth, seventeenth, eighteenth, and 

 nineteenth classes of Linnaeus.* In the twentieth class 

 of Linnaeus, which includes the great family of Orchids 

 (fig. 4, b), the stamens are borne above the pistil, both of 

 which are of a special nature, as also those of the 



Swallow-wort family (fig. 4, c and d). (See character of 

 these families.) 



When the stamens are numerous in a flower, they ge- 

 nerally vary in length ; but in the Labiate and Cruci- 

 ferous families they are always of a definite length with 

 regard to one another. In the former, there are four — 

 two long and two short (fig. 3, a) ; in the latter, six — 

 four long and two short (fig. 3, b). These characterize 

 the fourteenth and fifteenth classes of Linnaeus. 



Stamens present three modes of attachment : — First, 



* See Classification. 



