260 



PLANT LIFE. 



as in a head (*f 104), the receptacles are joined to form a 

 large common receptacle, as in the sunflower and its allies 

 (fig. 281). The receptacle in such plants may be a cone, 

 a dome (fig. 409), or a more or less flattened disk. In the 



FIG. 288. FIG. 289. 



FIG. 288. Flower of sweetbrier rose, halved; showing urn-shaped torus. Compare fig. 



139. Natural size. After Bessey. 

 FIG. 289. The inflorescence of fig, halved lengthwise ; showing common torus on 



whose interior surface many flowers are formed. Two fig wasps are near the opening 



of the flower chamber, one outside, while the other has just crawled in among the 



flowers. Natural size. After Kerner. 



fig the common receptacle is pear-shaped, with the edges 

 almost meeting above and the flowers distributed over the 

 inner face of the fleshy sac (fig. 289). 



III. Brood buds, etc, 



361. Definition. Single-celled spores pass without any 

 sharp distinction into the multicellular bodies known as brood 

 buds. For convenience, however, brood buds may be de- 

 fined as multicellular (sometimes unicellular) bodies capable 

 of producing a new plant of the same phase as that from 

 which they arise. Since this is a distinction for conve- 

 nience merely, it is not desirable to distinguish brood buds 



