436 BOTANICAL GAZETTE [November 



were allowed to remain upon the original solution on which the spores 

 had been sown. A luxuriant growth of algae developed in all of the 

 cultures, which added to the unfavorable growing conditions. 



March 9, 191 7, in both series of cultures, apogamous embryos were 

 observed on the prothallia which developed in Knop's full solution from 

 spores collected in Maine. Archegonia were developed on many of the 

 heart-shaped prothallia, while in some of the cultures on the smaller 

 prothallia antheridia were present. Some of the archegonia appeared 

 aborted. In most cases the apogamous embryos developed in the 

 manner which has previously been described. However, a few cases of 

 peculiar development were observed. Multicellular hairs or outgrowths 

 formed at the base of the first leaf or leaves of the young sporophyte, or at 

 various places on it. 



On one prothallium a long cylindrical outgrowth several cells in 

 thickness developed from the cellular mass along with the leaves of 

 the apogamous sporophyte. As growth proceeded, this outgrowth 

 broadened out into a one-celled prothallium-like structure, after which 

 it again assumed the cylindrical shape bearing tracheids; at its apex it 

 tended to return to the prothallium structure. On another prothallium 

 an outgrowth which had developed from the notch of the prothallium 

 and projected as a narrow process broadened at the apex, forming a 

 slightly notched prothallium. 



The only cases of apogamy on prothallia developed from spores 

 collected at Ithaca, New York, occurred in the culture of Knop's full 

 solution which had been kept in the laboratory. Most of the apogamous 

 embryos originated from cellular masses formed on the prothallia, but 

 on one prothallium a cylindrical outgrowth bearing tracheids developed 

 from the cells in the notch. At the apex of this long cylindrical process a 

 cellular mass was formed, from which the leaves, root, and stem of the 

 apogamous embryo developed. 



Two series of cultures of Osmunda cinnamomea and 0. Claytoniana 

 were made at the same time, in the same manner, and placed under the 

 same conditions as the cultures of Phegopteris polypodioides. Apogamous 

 embryos were observed March 9, 191 7, on the prothallia in the following 

 solutions: Prantl's full solution, Prantl's solution with NH4NO3 omitted, 

 and Prantl's solution with MgS04 omitted. Some of the apogamous 

 embryos developed from cellular masses; others originated as cyHndrical 

 outgrowths containing tracheids, from the notch of the prothallia, bear- 

 ing at their apices cellular masses which gave rise to the leaves, root, 

 and stem of the sporophyte. On one prothallium an apogamous sporo- 

 phyte formed near the notch, while at its base a lobe of the prothallium 



