626 MOSSES AND FERNS 



before the nucleus has changed its form. They increase much in 

 length, and are very numerous. 



P. 237. The writer found in O. pendulum that the neck canal-cell 

 not infrequently became completely divided into two cells. The 

 ventral canal-cell is difficult to demonstrate, and it often looks as if 

 no ventral canal-cell were formed. Probably it is formed just before 

 the dehiscence of the archegonium, and is very transient. 



P. 238. Bruchmann (6) has given a very complete account of the 

 gametophyte of B. Lunaria, which closely resembles the younger 

 stages of B. Virginianum. The archegonia are on the dorsal surface, 

 as in B. Virginianum, and not on the ventral side, as Hofmeister 

 states is the case. 



P. 242. The writer collected the older prothallia of Helmintho- 

 stachys in Ceylon at the same station where Lang secured his material. 

 They were in forest land, which was subject to annual flooding, and 

 it is probable that this is necessary for the germination of the spores. 

 The gametophyte appears to be annual, dying after the establishment 

 of the sporophyte. 



P. 242. The development of the embryo was investigated by the 

 writer in Ophioglossum Moluccanum and 0. pendulum. (Campbell 

 (29, 33).) In both of these the first division is approximately trans- 

 verse and divides the embryo into two nearly equal cells, an 

 "epibasal" and "hypobasal." From the hypobasal cell, in both 

 species, a large hemispherical mass of tissue is developed, the foot, 

 while from the epibasal half the other organs of the young sporophyte 

 ultimately develop. 



Both species show an unexpected deviation from the usual fern- 

 type. In O. Moluccanum the epibasal portion develops into a 

 conical body, with a definite apical cell, and this later expands at the 

 summit into the lamina of the spatulate cotyledon, or primary leaf. 



In the middle region, deep in the tissue near the base of the foot 

 (probably from the epibasal tissue), there arises a group of cells which 

 begin tO' divide actively, and form the beginning of the primary root, 

 which grows downward in the same plane as the cotyledon, and push- 

 ing through the tissue of the foot, breaks through it and the overlying 

 gametophytic tissue, and penetrates into the ground. 



The root grows from a tetrahedral apical cell, and there is soon 

 evident an axial strand of elongated cells, the "stele" or young 

 vascular bundle, and this continues without interruption into the 

 corresponding stele of the young cotyledon. All that remains of the 

 foot is a slight enlargement in the middle of the young sporophyte. 



