THE SHAPES OF BRANCHES. 



131 



growing fungi shown in Fig. 196, there will be perceived a 

 kindred transition from radial to bilateral symmetry, occurring 

 under kindred conditions. The portion of the pileus next to 

 the side of attachment is undeveloped in this branched form 

 as in the simple form ; and in the one case as in the other, 

 the stem is modified towards the side of attachment. A di- 

 vision into similar halves, which, as shown in Fig. 196 e, might 

 be made of the whole fungus by a vertical plane passing 

 through the centre of the pileus and the axis of the support- 

 ing body, might here be made of the branch, by a vertical 

 plane passing through the centre of its pileus and the axis of 

 the main stem. Among aggregates of this order, the Alga?. 

 furnish cases of kindred nature. In the branches of Lessonia, 

 Fig. 37, may be observed a substantially- similar relationship : 

 their inner parts being less developed than their outer parts, 

 while their two sides are developed in approximately equal 

 degrees, they are rendered bilateral. 



223. These few cases introduce us to the more familiar 

 but more complex cases which plants of the third degree of 

 aggregation present. At a, b, c, Fig. 202, are sketched three 



homologous parts of the same tree : a being the leading 

 shoot; I a lateral branch near the top, and c a lateral 

 branch lower down. There is here a double exemplifica- 

 tion. "While the branch a, as a whole, has its branchleta 



