MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



^39 



one time was on an average 1.4 and in the normal specimen 2.2, the 

 etiolated measuring 6.82 by 9.56, while the normal measured 9.6 by 

 7.12, showing that while the size of the etiolated epidermal elements 

 was smaller than in the normal, the number of epidermal cells had 

 increased to meet the excessive elongation of the petiole, but this 

 multiplication has not been followed entirely by the stomata, although 

 some increase has been made. 



The cortical cells of the petioles gave measurements comparable 

 to those of the epidermis, being 163.45 by 29.5, while the normal 

 were 168.75 b}' 43.75, showing here also a multiplication of ele- 

 ments. The bast cells in the etiolated were 10.9 by 9.35, while the 

 normal were 11.05 by 9.195 showing a diminution in length, but a 

 slight increase in thickness. The walls are all thinner and only 

 traces of lignification were found in the xylem. 



The stomata on the leaflets measure 5 by 5.13 in the etiolated and 

 6.88 by 9.1 in the normal, showing an average of 6 in the field in 

 the etiolated, and 8.6 in the normal. A number of pre-stomatal ele- 

 ments were to be seen in the etiolated laminae, which never under- 

 went the final stages of development in darkness. 



The hairs on the etiolated leaves measure 281.25 by 5.05 in the 

 etiolated and 128.125 by 4.95 in the normal, thus exhibiting excessive 

 elongation, and but little increase in diameter. The marginal epi- 

 dermal cells of the leaf measured 6.64 by 5.92 in the etiolated speci- 

 men and 25.3 by 8.35 in the normal. The epidermis of the upper 

 surface measured 5.51 by 4.13 by 4.26 in the etiolated leaflet and 

 30.96 by 20.8 by 15.95 in the normal. Epidermal cells from the 

 lower surfaces measured 5 by 3.97 by 4.95 in the etiolated and 29.28 

 by 20.4 by 9.2 in the normal, from which it is. to be seen that an 

 increase in the actual number of cells follows etiolation in the 

 leaflets, as well as in the petioles. Differentiation into palisade and 

 spongy parenchyma did not ensue in the etiolated leaflet. 



The following determinations of ash, dry matter and water in 

 Oxalis lasiandra were made : 



I. Normal Leaves Including Petiole. 

 Weight of fresh material 3.13 grams. 



" dry " .219 " 



" ash " .03I " 



Percentage of water 93. 



" dried matter 7.00 



