82 



IOWA ACADEMY OF SCIENCES. 



liEAF I 



r ) L. .00109 inches. 



I Stoma 1 [ 



I ) W. .00094 " 



I ( L. .00109 " 



I Stoma 2 ■ 



I ( W. .00078 " 



Leap II... { 



Stoma 3 



Stoma 4 



Sto mal 



Stoma 2- 



Stoma 3- 



Stoma 4 



Stoma 



A 



Leap 111.. { 



Stoma 2- 



Stoma 3 



L. .00109 



W. .00086 



L. .00125 



W. .00078 



L. .00156 



W. .0C094 



L. .00125 



W. .00094 



L. .00094 



W. .00094 



L. .00125 



W. .00094 



L. .00139 



. W. .00109 



( L. .00094 



I W. .00078 



^ L. .00139 



W. .00109 



( L. .00125 " 

 I Stoma 4 -A 



t ( W. .00109 " 



The variation inditterent species may be seen in the table. Weiss' gives the 

 length and breadth of the stomata in forty species. The least length in his table 

 is .00047 in., the length of the stomata in Amaranius caudatus ; the least width is 

 .00031 in., in Morns alba; the greatest length is .00279 in., in Lilium bnlhifenim; 

 and the greatest v?idth is .00197 in., in Avena sativa. The average length of the 

 stomata in the forty species is .00126 in., and the average breadth is .00091 in. 



While studying stomata 1 also made some observations on palisade cells. The 

 number of rows of palisade cells in each species is given in the table. The number 

 varies from one to four, two bemg the most common number. Prof. Bessey^ found 

 from two to four rows in the various varieties of the apple. Except in vertical 

 leaves, palisade tissue is seldom found on the under surface of the leaf. Stomata 



7Gooclale's Phys. Bot., p. 171. 

 siowa Hort. Rep't, 1879, p. 132. 



