TERATOLOGY. SUPPRESSION OF ORGANS. 



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

 Tropaeolum pentaphyllum (fig. 542), there are five sepals, two petals, 

 eight stamens, and three carpels. In all these cases, the want of sym- 

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

 tioned 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. 542); there are two rows of stamens, hi each of 



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



instances the parts which are afterwards suppressed can be seen in the 



early stages of growth, and occasionally some vestiges of them remain 



in the fully developed flower. Sometimes 



the whorl of the petals is awanting, the 



llowers being apetalous (, privative, and 



3-TXo, a leaf) (fig. 543), and in such cases 



it is common to see the stamens opposite to 



the segments of the calyx, as in Chenopo- 



diacese (fig. 544). That this suppression of the petals takes place is 



shown in the case of certain allied plants, as in the natural orders 



Caryophyllaceae and Paronychiacese, where some species have petals 



and others want them. 



648. By the suppression of the verticil of the stamens or of the 



Fig. 539. Diagram of the flower of Staphylea pinnata. The parts of the calyx, corolla, arid 

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

 dimerous. 



Fig. 510. Diagram of the flower of Holosteum umbellatum. There are five calycine 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 unsymmetrical. 



Fig. 541. Diagram of the flower of Impatiens parviflora, with one of the calycine 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 suppression. 



Fig. 542. Diagram of the flower of Tropaeolum pentaphyllum, with a spurred or calcarate 

 calycine 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. 



Fig. 543. Diagram of the flower of Glaux maritima, showing the suppression of the verticil of 

 the corolla. There are five divisions of the calyx, five stamens alternating with them, and five 

 divisions of the ovary, with a central placentation. 



Fig. 544. Diagram of the flower of Chenopodium album, showing the suppression of the ver- 

 ticil of the corolla. The five stamens, in this case, are opposite to the divisions of the calyx, thus 

 exhibiting the arrangement which might be expected from a non-development of the corolla. 

 The divisions of the ovary are not easily seen, the placentation being central. 



