IOWA ACADEMY OF SCIENCES. 



b3 



are confined mainly to the under surface and palisade cells to the upper surface. 

 The nature ot the palisade tissue depends largely upon the amount of light 

 the leaf receives during its growth. Frequently the innermost layer of palisade 

 cells will be incomplete, that is, in places it will be absent, or the cells may be but 

 little ditterent from the ordinary parenchyma cells. In the table, incomplete layers 

 are indicated by the sign +. 



The following table gives the results of some observations made during the past 

 summer. It gives the number of rows of palisade cells, the number of stomata per 

 square inch, and the size of the stomata in the species and varieties named. For 

 tlie species given in the latter part of the table the size of the stomata is not given. 

 I'artly dry and partly alcoholic material was used and in these conditions measure 

 ments of stomata would be unreliable, and hence are omitted: 



TABLE. 



STOMATA PER 

 SQ. INCH. 



Sugar pear (Pyfws communis) 



Rutabaga {Brassica compestrHs) 



Portukteca oleracea 



Salix laurifoUa 



Primus pennsuli'ctnica 



Polygonum cuspidatum 



PontecUria cordata 



Apple (Canada Baldwin) Pyrus mains. 



Apple (Peffer No. 1) Pyrus mains 



Apple (97S) Pyrus mains 



Nymphcea rcniform is 



Acer iiigrnm 



Pynui coronaria 



Cratcegns tomentosa, van. mollis 



Apple (Oldenburg) Pyrus mains 



Sagittaria variabilis 



Virginia Crab 



C M (Russian cherry) Prunus cerasus. 

 12 M (Russian cherry) Prunus cerasus. 



Silphium la/iiniatum 



Lactuca scariola 



Popidus certineimis 



Populus tfcmuki 



9,024 



21,150 















91,000 















458,332 











• 6,768 



12,690 



8,460 



135,000 



215,000 



62,500 

 118,332 

 290,000 

 123,332 



32,500 







350,000 



300,000 



L. .00085 

 W. .00075 



.00429 

 .00285 





 



L. .00094 

 W. .00078 







32,500 















45,000 



120.000 



43,750 



150,000 

 37,500 

 153,750 

 160,000 

 142,.500l 

 50,000 

 122,000 

 109,000 



L. .00182 



W. .00130 







Tj. .00102 



W. .00172 



L. .00101 



W. .0il0i)8 



L. .00130 



W. .00081 



JL. 

 I W. 

 JL. 

 1 W. 



L. 



W. 

 (L. 

 1 W. 

 JL. 

 I W. 

 JL. 

 IW. 



L. 



W. 

 JL. 

 |W. 

 (L. 

 I W. 

 JL. 

 .( W. 

 ) 



r 



(L. 

 "/ W. 

 JL. 

 ( W. 

 jL. 

 ( W. 

 IL. 

 "/ W. 

 JL. 

 MV. 

 S L. 

 'I W. 

 I L. 

 ■| W. 

 IL. 



W. 

 L. 

 W. 

 L. 

 W. 



.00151 / 

 .00119 f 

 .00119 I 

 .00079 f 

 .00070 I 

 .00092 f 

 .00150 / 

 .00143 f 

 .00107 ( 

 .OOO.'iO f 

 .00381 I 

 .00261 f 

 .00579 ( 

 .00266 f 

 .00125 / 



.00094 r 



.00128 I 

 .00086 f 

 .00115 / 

 .00093 )' 

 



.00073 r 



.00100 I 

 .00062 ( 

 .00102 ; 



.00084 r 



.00124 I 

 .00095 f 

 .00192 ( 

 .00156 I" 

 .00138 I 

 .00101 f 

 .00127 I 

 .00106 f 

 .00146 I 

 .00098 f 

 .00198 ( 

 .001.56 ( 

 .00101 ( 

 .00078 \ 

 .00114) 



.00070 r 



