26o MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



i68), J^nmex {p. 170), Sarracenia (pp. 173, 177) and Viola ohliqua 

 (p. 186). Of these the ternately compound leaves of Bicuculla, 

 which ordinarily undergo a bulbous enlargement of the basal por- 

 tion, did not unfold the laminae, which remained in a condition not 

 widely different from that shown in the bud, while the petioles did 

 not attain a length in excess of the normal. Notwithstanding this 

 failure to exceed the usual dimensions, the epidermal cells of the 

 petiole were twice as long as those of normal green organs. Sto- 

 matal openings were entirely lacking and the leaves were of brief 

 duration. Cyclamen offers an interesting comparison with the pre- 

 ceding by reason of the fact that the etiolated petioles were less 

 than twice the length of the normal, while the epidermal cells attained 

 a measurement of four or even five times the normal, the two exam- 

 ples demonstrating that the dimension of etiolated and normal organs 

 are not correlated with the measurements of the epidermal elements. 

 The laminae of Cyclauien were likewise not unfolded, but the petiole 

 was furnished with a number of stomata apparently functional, and 

 endured for several weeks. The petioles were apogeotropic, and a 

 succession of these organs was produced from the corms during 

 extended periods. The cauline leaves of Hydrastis developed 

 petioles about double the length of the normal with the reniform 

 laminae not unfolded, and the flower-bearing stems behaved in a 

 similar manner. 



A second phase of behavior of epidermal cells under etiolation is 

 offered by Oxalis lasiandra, the petioles of which reach a length 

 two to twelve times that of the normal. The increase in length is 

 accompanied by a multiplication of the epidermal cells which are 

 also slightly longer and narrower than in the normal. The laminar 

 portions remained in an unfolded position with no differentiation of 

 the tissues usually containing chlorophyl (p. 137). Only a few of 

 the stomata were differentiated, numerous prestomatal elements with 

 densely granular contents being discernible. The petioles were apo- 

 geotropic, falling over by their own weight, being thicker than the 

 normal, and with the terminal portions curved upward. Oxalis vio- 

 lacea did not show such marked elongations of the petioles in dark- 

 ness as the above-named species, and the tissues of the leaf reached 

 a more advanced stage of development, with a relatively larger num- 

 ber of stomata, the laminae being held in an extended position ap- 

 proximating the normal stature. One striking feature exhibited by 



