Vol. 44 T O R R E Y A April 1944 



On the Concept of Type 



Alfred Rehder 



In a footnote appended to an article on "Polypetalous Forms of Vaccinium" 

 (Torreya 42: 173. 1942) Camp and Gilly write: "One wonders how the 

 apparent basic, normal material can be considered a variation of an obviously 

 derived and abnormal, vegetatively propagated clone (and therefore, biologi- 

 cally an individual) except where nomenclature is an end in itself rather than 

 a means by which information can be better organized. The writers of this note 

 bow to the accusation that they hold to the principle that nomenclature, as such, 

 should be a tool in the science of systematics, rather than the view that system- 

 atics is a mental diversion appended to the science of nomenclature." 



Camp and Gilly are certainly right in asserting that nomenclature should 

 be a tool in the science of systematics ; that is what nomenclature should be and 

 is. Its aim is to make it possible to designate by certain names certain groups of 

 plants and to assure the greatest possible stability of these names. To attain this 

 aim it is necessary to provide rules to be followed in applying names to groups 

 of plants. As the two basic principles to attain the greatest possible stability, 

 the principle of priority of the names proposed and the type concept have been 

 generally accepted. In regard to the type concept Camp and Gilly seem to be 

 confused in so far as they are apparently not aware that there are two kinds of 

 types in taxonomy, namely the nomenclatural type and the biological or phylo- 

 genetic type. The nomenclatural type of a species or subdivision of a species is 

 the plant or specimen (or in some cases a description or figure) upon which the 

 name is based, therefore the term "typicus" used as a name for a subdivision 

 of a species refers to the nomenclatural and not to the biological type. The type 

 of a genus is the species, and the type of a family is the genus, upon which the 

 name is based. If a name is based on several species or on several genera simul- 

 taneously without the author indicating a certain group as type, the group 

 which best represents the concept of the author is to be selected as lectotype. 



In most cases the nomenclatural type and the biological type are identical, 

 but there are cases when the nomenclatural type is clearly a derivative of the 

 group representing the biological type, as in Rhododendron linearifolium of 

 which Camp and Gilly say: "One wonders how the apparently basic normal 

 material can be considered a variation of an obviously derived vegetatively 

 propagated clone . . ." but the fact is that no one considers R. macrosepalum 

 Maxim, a variation or derivative of R. linearifolium, and even Makino who 

 proposed in 1908 the combination R. macrosepalum var. linearifolium changed 

 it in 1913 to R. linearifolium a. linearifolium and called the biological type 

 R. linearifolium /?. macrosepalum, because R. linearifolium Sieb. & Zucc. of 



