252 



PLANT LIFE. 



rise to a plant of the other or sexual phase ; the sporophyte 

 produces the gametophyte. (For a description of the plant 

 thus formed see ^[ 385.) 



353. Perianth.- -The perianth is not present in any 



FIG. 272. A, hanging flower of milkweed, seen from the side. The petals are sharply 

 reflexed. Natural size. B, the upper part of same, magnified about 2^ diam., with 

 two of the appendages, a, of the stamens cut off and the front of the anther wall dis- 

 sected away to show its two pollen masses. C, two pollen masses from neighboring 

 anthers connected to a clip, by which they may be attached to the foot of an insect. 

 Magnified about 8 diam. D, foot of an insect with pollen masses attached. In Cand 

 D the pollen masses are inverted as compared with their position in A and B. After 

 Kerner. 



gymnosperms (^j 333), except in a rudimentary form in a 

 few species of the highest order. In angiosperms the 

 perianth, which is rarely wanting, is primarily for the 

 protection of the sporophylls. As in all cases where leaves 

 are produced rapidly and in close proximity on a short 

 axis, they grow during their early stages more rapidly 

 upon the outer face than the inner. They are, therefore, 

 concave inward and closely pressed together, forming a bud. 

 At a certain stage the growth upon the two faces of the 



