264 BOTANY. 



tute of fibro-vascular bundles and with minute flowers of 

 simple structure, may be contrasted with the Heaths, Com- 

 posites, and Madderworts. The highest development, all 

 things considered, is undoubtedly reached in the Compos- 

 ites: this is indicated by the number and variety of their 

 tissues, the high differentiation of the epidermal structures, 

 the aggregation of their flowers into heads, and these 



Fig. 143. — Marsh-marigold (Caltha palustris), with showy yellow perianth. 



often into secondary clusters; by the union of the parts 

 of the flower; by its inferior ovary with its single ovule; 

 its well-developed embryo; as well as by many other 

 things which we have not space to explain here. 



636. As to the arrangement of the Dicotyledons, it is 

 probable that a natural disposition of the orders would 

 place the ChoripctalsB below the Gamopetalje, the latter ex- 



