I02 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



were 15 cm. in length, and 2.5 cm. wide, while the normal leaves 

 are 8 by 3.2 cm. 



Epidermal cells from the lower surfaces of the etiolated leaves 

 measured 32 by 4 while those of the normal were onl}'^ 15 by 10. 

 Etiolated leaves bore glandular hairs only, the pointed trichomes 

 being absent. The shaft of the glandular hairs in the normal, con- 

 sists of two cells with an average total length of 50 and diameter of 

 4, while in the etiolated the shaft was composed of four cells of an 

 average total length of 110 with a diameter of 12. The apical gland 

 measured 22 by 19.5 in the etiolated, and 16 by 13 in the normal. 



From the above facts it is to be seen that the growth of Cypri- 

 pediuni in darkness is characterized by a non-development of the 

 pointed hairs on the leaves, and the excessive development of the 

 glandular trichomes. The first result is in accord with Schober's re- 

 sults, but no reason is at hand to account for the excessive enlargement 

 of the glands and the multiplication of the cells in the stalk, unless 

 these organs might be considered as aids to transpiration. The 

 stomata of the leaves were of normal size, but of slightly attenuated 

 outline, being apparently functionally normal. 



The laminae maintained an erect position, and were more or less 

 rolled during all of the period of their existence, embracing about a 

 month. 



Delphinium exaltatum Ait. 



A number of rootstocks of Delphinium exaltatiwi were potted 

 and brought into the dark room on January 18, 1900, and began to 

 grow at once. The main stem attained a length of 8 cm. as against 

 the normal of 4 cm. and the total height was 28 cm. while normal 

 plants under similar conditions were only 15 cm. high. The etio- 

 lated petioles reached a length of 10 to 30 cm. while the normal 

 measured only 4 to 6, thus showing the most excessive elongations 

 in the petioles. The petioles assumed a negatively geotropic posi- 

 tion with the laminae pendent by means of a curvature at the extreme 

 tip of the petiole. The actual rate of growth was about twice that 

 of the normal, during a period of ten days kept under observa- 

 tion. 



An etiolated specimen was cut off and the base of the shoot 

 thrust into water in a calibrated measure, through a cork which 

 was smeared with vaseline to prevent evaporation from the water 

 surface. The total volume of the exposed stem was 5 c.c. and 



