16 BIOCHEMICAL SYSTEMATICS 



overtones. Whatever the argument against the incorporation of phy- 

 logeny in classificatory systems, it seems obvious that if plants are 

 arranged in as close a phylogenetic order as possible, along somewhat 

 practical lines,^ the taxonomist has performed a service, however 

 small, to the biochemist interested in natural plant products, to the 

 geneticist interested in making realistic crosses, or to the pharm- 

 aceutical worker in his efforts to locate new sources of drugs. In 

 addition to these factors, as noted previously, phylogeny provides in- 

 tellectual vitality to taxonomy. 



Actually, most phylogenetic workers are cognizant of the 

 speculative nature of their various systems, but many outside of the 

 field are not fully aware of the tentative nature of differing and often 

 contending systems. The fact that evidence is not available to prove 

 or disprove one of two contending hypotheses concerning a particular 

 relationship does not invalidate the system as a framework for future 

 investigations. As new evidence accumulates, one of two competing 

 systems may increase in favor. Indeed, the two may be replaced by a 

 third which, while perhaps incorporating parts of both previous sys- 

 tems, may be substantiated with new evidence and information which 

 were not available to previous workers. 



Systems of classification 



Lawrence (1951) in an excellent treatment of the history of 

 classification stated that: 



Many different classifications of plants have been proposed. They are 

 recognizable as being or approaching one of three types: artificial, 

 natural, and phylogenetic. An artificial system classifies organisms for 

 convenience, primarily as an aid to identification, and usually by 

 means of one or a few characters. A natural system reflects the situa- 

 tion as it is believed to exist in nature and utilizes all information 

 available at the time. A phylogenetic system classifies organisms 

 according to their evolutionary sequence, it reflects genetic relation- 

 ships, and it enables one to determine at a glance the ancestors or 



the taxonomist now must make a formal name change, replacing the generic name, and, 

 if necessary, the specific name. But, why make the change? Changing the name doesn't 

 change the plant. What is gained by such action? 



The answers should be obvious. The previous position of the species was un- 

 natural and phylogenetically unsound. The scientist must recognize natural relationship 

 or phylogenetic position by making the appropriate transfer and resulting name change. 

 The latter is only incidental to the primary purpose in this redisposition. 



* Other systems might be easier to erect, maintain, and use for identification pur- 

 poses, but the utility often ends there. 



