246 



ORGANOGRAPHY. 



thecce. A young anther always possesses, as we have seen, 

 four loculi, and this is considered the normal state. When a 



Fig. 502. 



Fig. 504. 



Fig. 505. 



Fig. 502. Quadrilocular anther of the Flowering 

 Rush {Butomus umbeUatus). a. Filament bear- 

 ing an entire anther, b. Section of the anther 



with its four loculi Fig. 503. Androeciunn of 



Milkwort {Pohjgala), with one-celled anthers 



dehiscing at their apex Fig. 504. One of 



the stamens of the Lady's Mantle {Alchemilla). 

 'Die anther is unilocular or one-celled, and de- 

 hisces transversely. 



fully developed anther exhibits a similar 

 structure, as in the Flowering Rush (Bu- 

 tomus umbeUatus), it is four-celled, quadri- 

 locular, or tetrathecal (fig. 502); or when as 

 is more commonly the case, the partitions 

 separating the two loculi of each anther- 

 lobe become absorbed, it is two-celled, 

 bilocular, or dithecal (Jig. 490). In rare 

 cases, the anther is unilocular or one- 

 celled, as in the Mallow, Polygala 

 (fi.g. 503), Alchemilla (fig. 504) : this 

 arises, either from the abortion of one 

 lobe of the anther, or by the destruction 

 of the partition wall of the two lobes as 

 well as of the septa between the loculi of 

 each lobe. In some plants again, as in 

 many species of Salvia, the connective 

 becomes elongated into a kind of stalk, 

 each end of whicli bears an anther lobe 

 (fig. 505), in Avhich case there appears 

 to be two monothecal or unilocular anthers. 

 When this occurs one lobe only If con- 

 tains pollen, the other Is is sterile. 



That surfoce of the antlier to which 

 the connective is attaclicd is called the 

 back (fig. 501, A, «), and the 0])posite 

 surface is the face. The latter always 

 presents a more or less grooved appearance (fig. 501), indi- 

 cating the point of junction of the two lobes. Each lobe 

 again commonly presents also a more or less evident fur- 



Fig. 50.5. Stamen of 

 the Sage. /. Fila- 

 ment, c. Connective 

 bearing at one end 

 a loculus If, con- 

 taining pollen, when 

 it is said to be fer- 

 tile ; and at tlie other 

 end a loculus /,-.-, 

 without pollen, in 

 whicii case it is ste- 

 rile. 



