244 ORGANOGRAPHY. 



used in their ordinary acceptation. When the filaments are all 

 turned towards one side of the flower, as in the Horse Chestnut. 

 Fraxinella, and Amaryllis, they are said to be declinate. 

 Generally speaking the direction is nearly continuous from one 

 end of the fihimcnt to the other, but in some cases this is 

 departed from in a remarkable manner, and the upper part 

 of the filament forms an angle more or less obtuse with the 

 lower, the filament is then termed geniculate, as in the Mahernia. 

 This a])pearance commonly arises from the presence of an 

 articulation at the point where the angle is produced, as in 

 Euphorbia {fig. 497). In such a case, or whenever an articula- 

 tion exists on the apparent filament, this is not to be considered 

 as a true filament, but to consist in reality of a flower-stalk sup- 

 ])orting a single stamen. The flower here therefore, is reduced 

 to a stalk bearing a single stamen, all the parts except it being 

 abortive. This is proA-ed by the occasional production in 

 some allied plants of one or more whorls of the floral envelopes 

 at the point where the joint is situated. In the Pellitory the 

 filament assumes a spiral direction. 



The filament usually falls olF from the thalamus after the in- 

 fluence of the pollen has been communicated to the pistil, — that 

 is after the process of fertilization has been completed. In 

 rare cases, as in the Campanula, it is persistent, and remains 

 attached to the ovary in a withered condition. 



2. The Anther. — Its Development, and Structure. — Like the 

 leaf, the anther is first developed as a little cellular protuberance, 

 the apex being formed first as is also the case with that organ, 

 and the whole completed like the lamina of 

 Fig. 498. the leaf before the formation of the fila- 



ment or stalk. At first the cellular pro- 

 tuberance is solid {fig. 498), and exhibits 

 no appearance of cavities apart from those 

 common to all cellular structures ; at an 

 early age, however, we may observe the 

 fonnation of an epidermal layer ce, 

 sun-ounding the mass of cellular sub- 

 stance ci in its interior. As growth ad- 

 vances the cellular mass becomes altered 

 at certain points, usually at four (two of 

 which are placed in each halfof the anther,) 

 j^. 4j)g ^ . . {fiy-'i- 499 and 500), by the formation of 



'of a young "^ai)t*fer"!!f ^'^ many masscs cm of large cells, which 

 the jfeion (Cinntns uudcrgo a spccial development to be 



J/rlo). ce. Cells at the ,. j i •• i ^ i *i i 



circumference forming attcrwards dcscnbcd, to produce the pol- 

 nn epi.iermni layer. ]en ; each of thcsc masscs is surrouudcd 



CI. Internal cellB. Irom , • i i i • i i • . i r 



Maout. by a Special layer which ultiinatcly forms 



the inner lining of the anther, cl. As 



these aggregations of cells continue to develop tlicy press upon the 



