344 BIOCHEMICAL SYSTEMATICS 



morphology in some of its more trivial expressions (that is, leeif shape, 

 pubescence, aberrations of floral morphology, and so on). If we project 

 the present situation into the future, we conclude that there is in the 

 final analysis a much better chance of expressing specific biochemical 

 differences in precise genetical terms (including characterization of 

 the enzyme involved). Therefore, although the art of assessing the 

 phylogenetic value of morphological data is farther advanced than 

 the art of assessing the phylogenetic value of biochemical data, £ind 

 we know far less at this time about variation in the chemistry of the 

 plant, it is probable that in fifty years this situation will be reversed. 

 Form is so subtly, delicately, and especially so indirectly regulated 

 that its underlying genetics and biochemistry are likely to remain 

 among the most intractable problems in biology for a long time. In 

 fact, an understanding of morphogenesis requires first that its bio- 

 chemical basis be understood. 



