130 ELEMENTARY STUDIES IN BOTANY 



79. The sporophyte. --The habit of the sporophyte, as 

 its general appearance is called, shows every possible variation, 

 as would be expected in so large a group. One of the 

 oldest groupings of plants recognized this fact in classifying 

 them as herbs, shrubs, and trees. Of course these names 

 are retained for general use, but they cannot be denned 

 with exactness. 



The sporophyte is extremely variable not only in habit, 

 but also in structure. In general, the structure of the stems 

 and leaves is quite different from that found among Gymno- 

 sperms, almost every trace of the ancient fern connection 

 having disappeared. The root, stem, and leaf are such 

 important organs that they deserve separate treatment, and 

 this has been deferred until the greatest display of these 

 organs has been reached in the Angiosperms. Their place 

 in the history of the plant kingdom has been stated, but it 

 remains to consider their work, especially as such knowledge 

 is essential to any intelligent cultivation of plants. This 

 subject will be treated in subsequent chapters. 



80. The flower. The most characteristic structure of 

 Angiosperms is the flower. This does not mean that all 

 Angiosperms have flowers, but that Angiosperms have de- 

 veloped the flower. In 61 (p. 107) it was stated that the 

 strobilus is the precursor of the flower. Throughout Gym- 

 nosperms the strobilus is the nearest approach to the flower, 

 and among the simpler Angiosperms the strobilus continues. 



It is necessary to have clearly in mind the distinction 

 between a strobilus and a flower. It is a distinction of con- 

 venience and riot of exactness, for the two structures grade 

 insensibly into one another. A strobilus is a group of sporo- 

 phylls, organized together so as to form a structure distinct 

 from the foliage-bearing part of the plant. A strobilus- 

 bearing plant, therefore, has two kinds of lateral members : 

 sporophylls. and leaves. A flower introduces a thirdJateral 

 member, the perianth, which is associated with the sporo- 



