ORGANS OF REPRODUCTION. 563 



are perfect, and four more or less imperfect; the latter are said 

 to arise from collateral chorisis, one stamen here being divided 

 into three parts. Other examples of this fonn are by some con- 

 sidered to be afforded by the flowers of many Hypericums {fig. 

 542), in these, each bundle of stamens is supposed to arise from 

 the repeated chorisis of a single stamen. Collateral chorisis 

 may be considered as analogous to a compound leaf which is 

 composed of two or more distinct and similar parts. Transverse 

 chorisis is supposed by Gray, and some other botanists, to have 

 its analogue in the ligule of Grasses {fitj. 351), as that append- 

 age occupies the same position as regards the leaf, as the 

 scales of the Lychnis, &c., do to the petals. 



Dr. Lindley beUeves that the whole theory of chorisis " is 

 destitute of real foundation for the following reasons: — 



" 1. There is no instance of unlining which may not be as well 

 explained by the theory of alternation. 



" 2. It is highly improbable and inconsistent with the sim- 

 plicity of vegetable structure, that in the same flower the mul- 

 tiplication of organs should arise from two wholly different 

 causes; viz., alternation at one time, and unlining at another. 



" 3. As it is known that in some flowers, where the law of 

 alternation usually obtains, the organs are occasionally placed 

 opposite each other, it is necessary for the supporters of the 

 unlining theory to assume that in such a flower a part of the 

 organs must be alternate and a part unlined, or at one time be all 

 alternate, and at another time be all unlined, which is entirely 

 opposed to probabihty and sound philosophy. 



" 4. The examination of the gradual development of flowers, 

 the only irrefragable proof of the real nature of final structure, 

 does not in any degree show that the supposed process of un- 

 lining has a real existence." (Lindley 's "Introduction to 

 Botany," vol. i. p. 333.) 



According to Lindley's view, therefore, whenever the organs 

 of adjacent whorls are opposite to each other instead of alter- 

 nate, this is supposed to arise from the suppression of a whorl 

 which should be normally situated between the two that are 

 present. 



It would not be perhaps difficult to show, that the above 

 reasoning of Dr. Lindley's is incorrect, but the present work is 

 not adapted for the discussion of such a subject, as it Avould 

 require more space than we could atford for its suitable investi- 

 gation. To those who would wish to make themselves further 

 acquainted with this matter, I would refer them to Gray's 

 " Botanical Text Book," where the theory of chorisis, as well as 

 the theoretical structure of the flower generally, is most ably 

 treated of. 



3. Suppression or Abortion, — The suppression or abortion 

 of parts, may either refer to entire whorls, or to one or more 



