864 



SCIENCE 



[N. S. Vol. XXXVII. No. 962 



Dr. J. Argyll Campbell, junior assistant 

 to Professor Sehafer at Edinburgh University, 

 has been appointed professor of pliysiology in 

 the University of Singapore. 



W. Dawson, M.A., D.Sc. (Agr.), has been 

 appointed to succeed Mr. A. Henry as reader 

 in forestry at Cambridge University. Mr. 

 Dawson has held a similar position at Aber- 

 deen University. 



Peofessor Strasburger, of Breslau, has 

 accepted the position of director of the newly- 

 established medical policlinic and therapeutic 

 course at Frankfort-on-the-Main, which are 

 to be considered a department of the proposed 

 university. 



Professor Kaiserling, of Berlin, has ac- 

 cepted the appointment as successor of Pro- 

 fessor Henke at the Cologne Institute of 

 Pathology. 



DISCUSSION AND COBSESPONDENCE 



TYPES OF SPECIES IN BOTANICAL TAXONOMY 



It is becoming more and more evident that 

 only by the use of the method of types^ can 

 any stability be secured in taxonomy. In spite 

 of a growing realization of this fact there has 

 been no adequate appreciation on the part of 

 botanists of the great advantages offered by 

 plants over animals in the facilities they 

 afford for the multiplication of type material. 



Primary Types 

 Although the author of a new species usu- 

 ally has at his disposal several different speci- 

 mens upon which he bases his description, 

 nevertheless only a single twig or shoot to- 

 gether with any organs borne on it can be 

 considered to be the true type specimen. It 

 is not permissible to accept as parts of the 

 type other twigs or stems, for it often hap- 

 pens that they were not collected from the 

 plant that yielded the true type specimen and 

 subsequent research may show them to belong 



>Cook, O. F., 1898, "The Method of Types," 

 in Science (N. S.), 8: 513-516, No. 198, October 

 14. Cook, O. F., 1900, "The Method of Types in 

 Botanical Nomenclature," in Science (N. S.), 

 12: 475-481, No. 300, September 28. 



to a different variety or even to a different 

 species. Experience has shown that the au- 

 thor of a species is far from infallible, and 

 that to accept his verdict on this point may 

 give rise to a complete misunderstanding of 

 the species on the part of later investigators 

 and cause endless confusion in the subsequent 

 literature. 



Even in case of dioecious or polymorphous 

 plants where it is obviously impossible for a 

 single specimen to represent all of the essen- 

 tial characters of the species, the twigs cut 

 from different forms are not to be considered 

 as parts of the type specimen. It is easy to 

 see that where several species occur in the 

 same region it is not always possible for the 

 author of the species to be sure that the dif- 

 ferent sexes or castes" represented in the ma- 

 terial at his disposal really belong to one and 

 the same species. It is necessary to designate 

 some one specimen as the type and to associate 

 with it as paratypes additional specimens of 

 the other sex or of the other castes that seem 

 undoubtedly to belong to the same species 

 Usually the pistillate specimen will be desig- 

 nated as the type.' 



Even in case of a number of specimens pre- 

 sumably cut from the same plant it is unsafe 

 to consider more than one of them as the type 

 since there is always the chance that two 

 plants growing close together were not distin- 

 guished. Abnormalities or bud variations on 

 the type plant might also be overlooked, par- 

 ticularly if the collector, not realizing that he 

 was dealing with a new species, exercised no 

 unusual care. 



The type specimen is therefore unique, and 

 can not exist in duplicate. Types are the 



' Cook has discussed in some detail the various 

 castes of plants having definitely specialized 

 heterism (ropism). Cook, O. F., 1907, "Aspects 

 of Kinetic Evolution," in Proceed. Wash. Acad. 

 Sci., 8: 369-378, February 13. 



' The term allotype, although proposed for pale- 

 ontological material, might very properly be ap- 

 plied to any paratype possessing some very impor- 

 tant organ or distinctive feature not present in 

 the type itself. Burling, Lancaster D., 1912, 

 "The Nomenclature of Types," in Journ. Wash. 

 Acad. Sci., 2: 519-520, No. 21, December 19. 



