ORGA^rS OF REPEODUCTION. 355 



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 reason- 

 ing of Dr. Lindley's is incorrect, but the present work is not 

 adapted for the discussion of such a subject, as it would require 

 •more space than we could afford for its suitable investigation. 

 Those who would wish to make themselves further acquainted 

 with this matter, I would refer 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 or- 

 gans of a whorl. We shall treat this subject briefly under these 

 two heads. 



a. Suppression or abortion of one or more whorls. — We have 

 already stated that a complete flower is one which contains 

 calyx, corolla, audroecium, and gyncecium. When a whorl is 

 suppressed, therefore, the flower necessarily becomes incomplete. 

 This suppression may either take place in the floral envelopes, or 

 in the essential organs. 



Sometimes one whorl of the floral envelopes is suppressed, as 

 in Chenopodium {fig. 423), in which case the flower is apetalous 

 or monochlamydeous ; sometimes both whorls are suppressed, as 

 in Eupliorhia {fig. 495) and common Ash {fig. 424), when the 

 flower is naked or achlamydeous. 



When a whorl of the essential organs is suppressed, the flower 

 is imperfect, as it then by itself cannot form seed. The andrce- 

 cium or gyncecium may be thus suppressed, in either of which 

 cases the flower is unisexual. When both andrcecium and g^Tioe- 

 cium are suppressed, as in certain florets of some of the Compo- 

 sitse, &c., the flower is neuter. When the stamens are abortive, 

 the flower is termed pistillate ; or when the pistil is absent, sta- 

 minate. The terms monoecious, dioecious, and polt/gamous, which 

 have reference to this point, have been already sufiiciently ex- 

 plained (see p. 233). Some botanists, as already noticed (p. 353), 

 consider that when the organs of adjacent whorls are opposite to 

 each other instead of alternate, such an arrangement of parts 

 arises from the suppression of an intermediate whorl; but this 

 view is manifestly insufficient to account for such a circumstance 

 in all cases. Thus in the Khamnacese {fig. 774), the stamens 

 are opposite to the petals, and frequently united to them at the 

 base, and we cannot but regard them as produced by transverse 

 chorisis from the petals. In some cases, therefore, we regard 

 the opposition of the parts of contiguous whorls to be due to 

 suppression, and in others to chorisis. 



- b. Suppression of one or more organs of a whorl. — This is a 

 very common cause of deviation from normal structure ; we can 

 here only bring forward a few examples. 



AA 2 



