140 



MANUAL OF BOTANY 



plants (fig. 260), we have five sepals, five petals, ten stamens, 

 and only one carpel, four of the latter being here suppressed ; in 

 plants of the order Compositse the calyx, corolla, and androscium 

 have each commonly five members, but only two carpels are 

 present. 



In some species of Impatiens (fig. 261) we have five carpels. 



Fig. 259. 



Fig. 260. 



Fig. 261. 



Fkj. 259. Diagram of the flower of the Heartsease ( Viola). Fig. 260. Dia- 

 gram of a Leguminous flower. Fig. 261. Diagram of the flower of 



Impntiens parmfiora. 



five stamens, and five petals, but only three sepals ; here two 

 sepals are suppressed ; in Tropceoluni xientaphyllum (fig. 26?.), 



Fig. 262. 



there are five sepals, and but two petals, three 

 of the latter being here abortive. In the Labiatse 

 and Scrophulariacese one of the stamens is com- 

 monly suppressed, and sometimes three ; thus 

 in Lamitim we have five parts to the calyx 

 and corolla, but only four stamens ; and in 

 Salvia we have also five parts to the calyx 

 and corolla, but only two stamens. 



Besides the above examples of the suppres- 

 sion of parts, there is another kind of suppres- 

 sion, to which the term ahortion more properly 

 /•'i</. 262. Diagram of applies. This consists in ihe degeneration or 

 transformation of the parts of a flower. Thus 

 in Scrophularia the fifth stamen is reduced to 

 a scale ; in the TJmbelliferEe the limb of the 

 calyx is commonly abortive, while in the Compositse it is either 

 abortive (fig. 291), or membranous (fig. 292), or reduced to the 

 form of a number of hair -like outgrowths known as a pappus. 



Stamens which have undergone such degeneration are known 

 as staminodes. The anther is usually replaced by a somewhat 

 foliaceous expansion which has no pollen-sacs. 



the flower of Ti-o- 

 pmolum penta- 

 phylliim. 



