366 



TERATOLOGY — SUPPRESSION OF ORGANS. 



has led to many important conclusions relative to the development of 

 organs, and it is only by tracing the parts of plants through all their 

 stages and transformations that correct ideas can be formed as to their 

 relations and forms.* 



By suppression is meant the non-appearance of an organ at the 

 place where it ought to appear if the structure was normal, the organ 

 being wanting to complete the symmetry. This suppression is liable 

 to occur in all the parts of plants, and gives rise to various abnormali- 

 ties. Suppression may consist in the non-appearance of one or more 

 parts of certain verticils, or of one or more entire verticils. In the 

 flowers of Staphylea (fig. 638) there are five parts of the calyx, five 

 petals, five stamens, and only two carpels ; in many Caryophyllacese, 

 as Polycarpon and Holosteimi (fig. 639), while the calyx and coroUa 

 are pentamerous, there are only three or four stamens and three car- 

 pels ; in Impatiens noli-me-tangere (fig. 640) the calyx is composed 

 of three parts, while the other verticils have five ; in Labiate flowers 

 there are five parts of the calyx and corolla, and only four stamens ; 

 and in Tropseolum pentaphyllum (fig. 641) there are five sepals, two 





<^3 



Fig. 638. 



Fig. 639. Fig. 640. Fig. 641. 



petals, eight stamens, and three carpels. In all these cases the "want 

 of symmetry is traced to the suppression of certain parts. In the last- 

 mentioned plant the normal number is five, hence it is said that there 

 are three petals suppressed, as shown by the position of the two 

 remaining ones (fig. 64:1) ; there are two rows of stamens, in each of 

 which one is wanting, and there are two carpels suppressed. In many 



Fig. 638. Diagram of the flower of Staphylea pinnata. The parts of the calyx, corolla^ 

 and stamens are pentamerous, while the pistil, in consequence of the suppression of three 

 carpels, is dimerous. Fig. 639. Diagram of the flower of Holosteum umbellatum. There 

 are five ealycine divisions, and five petals ; but the stamens, by the suppression of one, are 

 only four in number ; while the carpels are, by suppression, reduced to three. Thus the 

 flower is unsymmetrioal. Fig. 640. Diagram of the flower of Impatiens parviflora, with 

 one of the ealycine leaves spurred. There are five carpels, five stamens, five petals, one of 

 which is larger than the rest, but only three parts of the calyx, in consequence of suppres- 

 sion. Fig. 641. Diagram of the flower of Tropseolum pentaphyllum, with a spurred or 

 calcarate ealycine leaf. The petals, by suppression, are reduced to two ; the stamens are 

 eight in place of ten, and the carpels three in place of five. 



* For a complete treatise on this subject, see Vegetable Teratology, by Dr. M, T. Masters. 



