344 swingle: botanical type specimens 



To sum up: Chemical stability is favored by various condi- 

 tions, but equality or approximate equality between the com- 

 bining masses is one of them. This is clearly an important 

 condition of stability, but it may be modified by any of the others. 

 In many instances the effect of mass equilibrium is conspicuous 

 and cannot be disregarded. The molecules of the diatomic 

 elements, H 2 , 2 , Cl 2 , N 2 , etc., in which two equal masses are 

 combined, may be regarded as typical stable compounds. 



BOTANY. — Clastotypes, clonotypes and spermotypes, means for 

 multiplying botanical type specimens. Walter T. Swingle, 

 Bureau of Plant Industry. 



In a recent number of this Journal I called attention to the 

 possibility of multiplying type material by the use of merotypes, 1 

 i. e., additional herbarium specimens collected from the plant that 

 furnished the original type specimen. 



In case of the types which now exist in herbaria one cannot 

 usually decide with certainty from what individual plant they were 

 taken, even in the case of recently described species. It is often 

 possible, however, to distribute to other herbaria fragments 

 of existing types and these, even if very small, often have a high 

 value. Such parts of types may be called clastotypes. 2 



If a photograph be taken of the type specimen before any frag- 

 ments are detached, it is easy to mark on a photographic print the 

 location of the clastotype cut away. A print so marked and pre- 

 served with the type serves to indicate its original condition, 

 while one sent with the clastotype shows its postion on the type 

 specimen. 



So valuable are types pecimens that every portion no matter 

 how small should be preserved. If a fragment is boiled and 

 studied it should afterwards be added to the alcoholic collection; 

 if examined under the microscope a permanent mount should 

 be made. Both the alcoholic specimens and the microscopic 



1 Swingle, Walter T. Merotypes as a means of multiplying botanical types. 

 This Journal 2: 220-222, no. 9, May 4, 1912. 



2 Clastotype (k\<x<tt6s broken; tvttos type). A part or fragment of the type 

 specimen of a species. 



