ANGIOSPERMS. 



545 



portion of the stamen remains very short, while the secondary filaments lengthen 

 considerably and subsequently present the appearance of a tuft springing from the 

 receptacle, the true nature of which can only be ascertained by the history of its 

 development. If, on the contrary, the primordial basal portion lengthens, as in 



Fig. 367.— Development of the flower of Hypericum perforatum ; I young flower-bud in the axil of the bract B, with its 

 two bracteoles bb, s the sepals, / first indication of the petals ; // middle part of a somewhat older bud, y rudiment of the 

 ovary, a, a, a the three stamens with the rudiments of their branches arising as protuberances ; /// a flower-bud of nearly 

 the same age as in //, but seen from the side, s a sepal, a a the stamens.y the ovary ; /y and F flower-buds in further 

 stages of development, the letters indicating the same as in /, //, and /// ; i, 2, 3 ovary in various stages of development cut 

 through horizontally. 



Calolhamnus, the whole stamen is easily recognised as branched even in the mature 

 condition. 



Of no less importance for understanding the entire plan of structure of a 

 flower, and especially the relations of number and position which actually occur, 



Fig. 368.— Development of the androecium of Cucurbtta Pepo (after Payer) ; in all the figures the simple stamen is to the 

 right, behind and to the left two double ones. The anthers grow vigorously in length and form vermiform coils. 



is the cohesion of stamens which grow side by side in a whorl. In Cucurbita, 

 for example, there are, in the earliest stage, five stamens, but at a later period only 

 three are found, two of which are, however, broader than the third ; these are each 



N n 



