THE FLOWER. 11 



in the Poplar, etc., is called a catkin or ament. A thick fleshy spike is 

 called a spadix, and this is often furnished with imperfect flowers, and 

 surrounded by a peculiar enveloping sheath, called a spathe; as seen in 

 the Calla, Indian Turnip, etc., or the spadix may be naked as in the 

 Cat-tail Flag (Typha). 



56. A Head is a form of inflorescence where the flowers are sessile 

 and springing all from a very short and somewhat enlarged axis, known 

 as the receptacle. The Button-ball, Button-bush, etc., afford familiar 

 examples. Sometimes the head is subtended by a whorl of bracts, called 

 here also an involucre, as seen in the Dandelion, etc. 



57. Determinate Inflorescence is a form where the flowers ap- 

 pear from terminal buds; consequently the further growth of the axis 

 in that direction there terminates. Should there be a single flower it is 

 spoken of as terminal and solitary. When there is a cluster of flowers 

 the order of blossoming is just the reverse of what we saw in the inde- 

 terminate type. It is descending, i. e., the uppermost flowers develop 

 first and the lower ones later. When they form a broad and flat flower- 

 cluster, those in the center open first and the outer ones later. Hence it 

 is said to be centrifugal in order of development. The cluster is spoken of as 



58. A Cyme the first flower appearing from the terminal bud, and 

 then at the ends of naked or bracted shoots from the nearest axillary 

 buds; then from the next lower and so on. (Fig. 25.) The simplest 

 form is just the reverse of a simple raceme. (Compare Figs. 21 - ^ 

 and 25.) When the branching continues further it becomes a \/ 

 compound cyme. (Fig, 26. ) > ( 



59. A Fascicle is a cyme where the flowers appear in a close \ Jf 

 cluster or bundle, as the origin of the name L. fasciculus, a 

 little bundle indicates, and 



60. A Glomerule is a cyme where the flowers appear in a 

 sort of head. These forms may be recognized by their centri- 

 fugal order of blossoming. Cyme 



61. Some plants represent both the determinate and the inde- p IG< 35 

 terminate systems of inflorescence, by having the flowers arranged 



in the clusters of one system and these clusters 

 developing in the order of the other. But both 

 systems are seldom, if ever, represented primarily 

 in one cluster; i. e., plants rarely, if ever, produce 

 flowers from loth terminal and axillary buds. 



THE FLOWER. 



62. The object of the flower, in vegetable econ- 

 . m y is the production of seed for the perpetua- 

 tion f the species. In its complete form it con- 

 sists of four parts, called the organs of the flower. 

 They are the calyx, corolla, stamen and pistil. 



63. Strange as it may seem at first thought, these parts, how- 

 ever peculiar in form or in color, are nothing more nor less than 

 altered leaves, differentiated for the special purpose of reproduction. 



Figs. 25-26. Forms of Determinate Inflorescence. 



