﻿PFEIFFER—OPHIOGLOSSUM VULGATUM 



occurs. In external appearance the prothallium may be dis- 

 tinguished readily from roots by the irregular form and uneven 

 surface it exhibits owing to the sex organs, as compared with 

 the straight and very smooth roots or rhizomes. The end is 

 more or less round or even tuberous, as indicated in Bruchmann's 

 figures, as compared with the pointed root tip. Usually in speci- 

 mens with well developed sporophytes, the decided brown coloring 

 of the prothallium is another distinguishing character, although 

 here it is often difficult to distinguish sharply between the base of 

 the sporophyte and the gametophyte. The younger material, as 

 well as the growing region of 

 older gametophytes, is lighter in 

 color, however. As compared with 

 the horizontal position of most of 

 the roots, the prothallium is usually 

 oriented with its long axis nearly 

 vertical. 



Sections of a prothallium with 

 a young sporophyte attached show 

 the surface to be well dotted with 

 sex organs (fig. 3), as may be 

 seen even in bulk material by use 

 of a hand lens. The necks of old 

 archegonia are conspicuous, as are 

 the positions of antheridia. Occa- 

 sionally there are antheridia still 



unshed, as shown on a small excrescence near the upper portion, 

 where fungal hyphae had not yet entered (fig. 4). Here it is 

 probable that there was continued production of sex organs 

 after fertilization. Sufficient material for working through de- 

 velopmental stages was not at hand, but the stages found confirm 

 Bruchmann's conclusions regarding the sex organs. 



The general topography does not differ from that figured by 

 Bruchmann, except that there is usually only one cortical layer 

 free from fungi. Within this is the region, 4-6 layers of cells deep, 

 in which the fungus is conspicuous, and then the central region, 

 staining more lightly because of the absence of mycelium in the 



Fig. 4— Section of 



