THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. IX, No. 20.] SEPTEMBER, 1915. [ v 1 ho x l i e x s no e Io 



Differentiation of the Oaks by Histological 



Methods. 



F. W. MULSOW. 

 Plates LX-LXIV. 



IN this work four species of native oaks are compared as to 

 their histological structures and characteristics. The 

 species studied are Q. rubra, Q. schneckii, Q. coccinea and Q. 

 macrocarpa, as classified by Britton and Brown. Branches, 

 leaves and acorns from one tree only of each species were 

 studied throughout their essential parts. But in the study of 

 Q. rubra and Q. schneckii three different trees were studied 

 in a few of their structures peculiar to themselves, in order 

 to find out the constancy of their characteristic structures. 

 Parts of the leaves were embedded in paraffin and sectioned 

 with the rotary microtome; also, some of the leaves were 

 bleached for studying the cell structure and leaf venation. 

 Parts of the branches were placed in dilute glycerine, this 

 making them easier to section. The double stain of safranin 

 and hematoxylin was used in differentiating the various tis- 

 sues. The staining for temporary mounts may be carried out 

 in one operation by mixing equal parts of each stain and 

 placing the sections in this mixture for a few minutes. After 

 washing in seventy per cent alcohol they are ready for study- 

 ing in dilute glycerine. For best results the stain should be 

 made up fresh just before using. 



Received for publication June 10, 1915. 



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 2 — Univ. Sci. Bull., Vol. IX. No. 2f 



