VIII 



THE PTERIDOPH YTA—OPHIOGLOSSA CEyE 



225 



could be detected. As growth proceeds, the oil partially 

 disappears, and the cells become much more transparent than 

 at first. Up to the present writing no further observations have 

 been made, but it is hoped later that some additional informa- 

 tion may be obtained on this important point. 



In July 1893, at Grosse He, Michigan, the writer was 

 fortunate enough to find a number of old prothallia of Botrych- 

 itnii Vtrginianuvi. They were all connected with the young 

 sporophyte, and were too old for studying at all completely the 



,1 ' . D 



Fig. no. — Botrychiiim P'irginianmn {Svf.). A, B, Germinating spore, x6oo; C prothallium {/»■), 

 with young sporophyte attached, X 2 ; D, longitudinal section of the prothallium, showing the 

 foot of the embryo {/), X 4 ; E, first (?) leaf of a young sporophyte, x 2. 



development of the sexual organs and embryo. They resembled 

 closely those of B. lunaria, but were very much larger. The}- 

 grew at a distance of several centimetres beneath the surface of 

 the ground, in the neighbourhood of a number of large speci- 

 mens of the mature plant. The prothallium at this stage, like 

 that of B. lunaria, is completely destitute of chlorophyll, and 

 has the form of a slightly flattened tuber, which in the larger 

 ones showed fold -like ridges upon the upper surface. The 

 outer cells were brownish, and short root-hairs grew in large 



Q 



