THE BRYOLOGIST. 



Vol. V. May, 1902. No. 3. 



SUN PRINTS IN BRYOLOGY. 



Dr. Rodney H. True. 



During the past ten years the writer has been engaged in the study of 

 the genus Dicranum, and, in casting about for some method of illustrating 

 a contemplated paper on the subject, has experimented with a number of 

 methods. Special difhcultyhas been encountered in finding some method of 

 placing before the reader an accurate representation of the general habit of 

 the plant. The somewhat costly service of the professional artist, while sat- • 

 isfactory in many respects, was found to present financial obstacles. 



At length it occurred to him that perhaps the method described by Dr. 

 Halsted, under the name of Solandi process of printing, applied by him to 

 leaves of flowering plants, might here be capable of adaptation. The 

 anticipation proved well founded, and at the suggestion of the editors of 

 The Bryologist, the writer has presented h^re a brief statement of the 

 method as used by him, and also illustrations (Plate IV, and Fig. A.), which 

 will serve to indicate the kind of results obtained. 



Fio. A. 



1. Board at back nailed to frame. 



2. Pad of cotton covered with tissue paper. 



3. Sheet of photographic paper. 



4. Moss. 



5. Piece of glass. ■ ' 



6. Frame. 



The method may be described briefly. The moss to be used should be 

 carefully chosen and prepared for the purpose. The tuft should not be so 

 thick as to wholly exclude light. The individual plants should be readily 

 distinguished. This tuft, dried under considerable pressure, is laid upon 

 the surface of some smooth sensitive paper, (solio is good,) and pressure 

 applied suflicient to give a close contact This is obtained by the writer in 

 the following manner: A board of proper size, (Fig. A.) perhaps six inches 

 by four inches, furnishes a soHd backing (i). On this is laid a pad, made by 



The March Bryologist was issued March ist, 1902. 



