MISCELLANEOUS 435 



ferns from spores. This ■^ill be of scientific interest rather than interest in 

 commercial propagation. Barrows discusses the structure and chemical 

 composition of the spores and the ability to adapt them to such commercial 

 uses as toilet powder and powder to prevent castings from sticking to the 

 sand in moulding. She found an endophytic fungus generally present in 

 gametophytes collected in nature, and agrees with Treub, Bruchmann 

 and others on the necessity of the fungus for gametophyte growth beyond 

 an early stage. She grew many cultures of the fungus but was unable to 

 identify it. 



The spore coats seem to offer resistance to the germination of the spores, 

 but other unknown factors present even greater difficulties in producing 

 mature gametophytes. Apparently gametophytes sometimes produce 

 antheridia but no archegonia. These of course cannot produce sporophytes. 



The sporophytes of Lycopodiinn can be propagated by cuttings or bul- 

 bils. Spring cuttings of L. clavatum L., L. complanatum var. flahelliforine 

 Fernald, and L. obscurum L. did better than fall cuttings. Fall cuttings of 

 L. lucidulum Michx. rooted well. L. lucidulum can be propagated from 

 bulbils, two crops of which are produced annually under greenhouse con- 

 ditions. Young apical growth of rhizomes roots readily; older, hgnified 

 material roots poorly. Lycopodium needs well-watered but well-drained 

 soil and, except for L. complanatum, some protection from direct simlight. 

 They grow in soils that range from 5.28, or perhaps lower, to 8 pH. An 

 endophytic fungus is found generally distributed in the roots and old parts 

 of the rhizome of all species studied. The fungus was cultured from several 

 species but not identified. 



Two Studies on Physiology and Cytology of Fungi 



After having found that when opposite sex strains of Neurospora sitophila 

 (Mont.) Shear & Dodge are gro^^^l in opposite arms of U-tubes filled with 

 nutrient agar no fusion of the two strains occurs to form perithecia until 

 the agar dries and cracks to supply oxygen at the base of the tube. Dr. 

 B. O. Dodge suggested to Denny ^^ that he determine the minimum oxygen 

 pressure necessary for filament fusion, perithecia formation, and growth of 

 the mycelia. At room temperature perithecia formed in 1 to 2 per cent 

 oxygen by volume, but reducing the oxygen to 0.5 per cent by volume 

 inhibited perithecia formation for at least 30 days, the duration of the 

 experiments. At 10° C (50° F) no perithecia form in any oxygen percentage 

 after 30 days, and only an occasional one at 15° C (59° F). Perithecia are 

 formed somewhat less readily at 31° C (88° F) than at room temperature. 

 Growth of the mycelivmi occurs under much lower oxygen pressure; 0.3 per 

 cent or higher gives rapid growth of the mycelium, but the rate of growth 

 diminishes as the oxygen percentage falls below this. At 0.01 per cent 

 oxygen the growth was very slow, but complete inhibition of growth occurs 

 only when the atmosphere over the culture is held free of oxygen by alka- 



