32 BULLETIN 1053, U. S. DEPARTMENT OF AGRICULTURE. 



on the submerged mycelium after about 10 days, but are empty and 

 dead in 2 months. 



The secondary spores of the four species considered here are 

 formed on all the nutrient media tried, although in varying quanti- 

 ties, but Lenzites sepiaria is the only species so far known to form 

 them on wood. Temperature has no appreciable effect on the forma- 

 tion of these spores on malt agar. Early in the work it seemed as 

 if light favored the formation of oidia by Lenzites sepiaria and that 

 darkness prevented it, but a variety of tests, variously checked, 

 failed to give absolutely consistent results. Yet it was found that 

 cultures started in the light nearly always formed oidia, while those 

 in the dark seldom did. 



GERMINATION STUDIES OF THE SECONDARY SPORES. 



The oidia of Lenzites sepiaria germinate readily and to practically 

 100 per cent on agar. The cylindrical oidia as a rule simply lengthen 

 out at either end or both ends with no swelling, so that no sign of 

 the original oidium is left (PL III, fig. 11). Germination may be- 

 gin, however, with a swelling of the oidium, at one end or in the 

 middle, and the germ tube may then arise from either the swollen or 

 unswollen ends (PL III, fig. 9). The club-shaped oidia which are 

 found occasionally may send out one or more tubes from either the 

 swollen or unswollen ends. In water the tubes are attenuated. The 

 chlamydospores of Le'nzites sepiaria germinate normally (PL III, 

 fig. 10). The oidia and chlamydospores of Lenzites trabea germi- 

 nate in a manner similar to those of L. sepiaria. The chlamydo- 

 spores of Trametes serialis (PL IV, fig. 9), and Lentinus lepideus 

 send out tubes from either end of the ellipsoid spores, although 

 usually from only one end. 



Germination tests were carried out upon the oidia of Lenzites 

 sepiaria and Lenzites trabea and the chlamydospores of Trametes 

 serialis. The chlamydospores of L. sepiaria and L. trabea were not 

 readily obtainable in sufficient quantities and were hard to separate 

 from the oidia. The chlamydospores of Lentinus lepideus could not 

 be obtained in a condition which would allow of their manipulation. 

 The chlamydospores of all four fungi occur chiefly, if not entirely, 

 on the submerged mycelium in the agar. Those of Trametes serialis 

 could be obtained in sufficient numbers by scraping the submerged 

 mycelium, with as little agar as possible, from the surface of the 

 culture, then macerating this material between two thick glass slides 

 which had been previously flamed and finally removing this macer- 

 ated mixture to sterile water blanks. The chlamydospores were 

 separated from the mycelium by this process and the mycelium 

 sufficiently injured so that it did not interfere with germination 



