46 KANSAS UNIVERSITY SCIENCE BULLETIN. 



erally much larger. The secondary veins of No. 4 were nearly 

 straight, those of No. 2 and 3 were curved. (Figs. 1 to 7.) 



The acorns showed the most marked macroscopic difference 

 between the four oaks. The acorns of No. 1 averaged 1.5 cm. 

 in length and width; No. 2 averaged 2 cm. long by 1.5 cm. in 

 width; No. 3 averaged 1.1 cm. in length by 1.2 cm. in width; 

 No. 4 averaged 1.6 cm. in length by 1.2 cm. in width. (Figs. 

 8, 9, 10, and 11.) Excepting No. 4, the cups were much alike, 

 being relatively deep and covered with thick bracts. No. 4 

 was shallow and covered with thin, tightly appressed bracts. 



The seeds varied in size in about the same ratio as the 

 acorns, except that No. 1 was relatively smaller on account of 

 the greater thickness of the shell. (Figs. 8 to 11 and 12 to 15.) 



The branches and twigs were much alike except that the 

 epidermis of Nos. 1 and 3 split up much earlier than that of 

 Nos. 2 and 4, making the twigs of the former rough while those 

 of the latter were smooth. 



The differences enumerated above formed the basis for the 

 microscopic study of the anatomy. 



PREPARATION OF MATERIAL. 



Material was prepared for sectioning by fixing in Fleming's 

 fixative and embedding in paraffin. Leaves were bleached in 

 chloral hydrate and potassium hydrate. In the study of the 

 wood, sections were made on the hand microtome from ma- 

 terial preserved in formalin and softened in dilute glycerine. 

 In tracing the middle bundle of the midrib, formalin-preserved 

 material was used, the sections being made on the hand mi- 

 crotome. 



BLEACHING. 



There was a notable difference in the length of time it took 

 to bleach the leaves in choloral hydrate. No. 1 bleached in 24 

 hours, No. 4 in 6 days, Nos. 2 and 3 in 7 days. In potassium 

 hydrate No. 4 was bleached in 24 hours, the others in 48 hours. 

 After bleaching, the leaves were stained 30 minutes in safranin 

 and decolorized in 70 per cent alcohol, which aided greatly in 

 differentiating the various tissues. Examination of the 

 bleached leaves under the microscope immediately revealed the 

 probable cause of the difference in time of bleaching. The 

 walls of the lower epidermis of No. 1 were very thin, almost 

 undistinguishable, while those of the others were relatively 

 thick. 



