330 DorAN: ON THE GERMINATION OF FUNGOUS SPORES 
production of sporidia by the teliospores of this fungus; aecio- 
spores of Gymnosporangium clavipes require four hours; conidia 
of Venturia inaequalis about twenty-four hours; and conidia of 
Sclerotinia fructigena five hours. These tests were all made at 
TABLE III 
Length of time required for the phe ie of the spores of 
representative fung 
| Hours necessa 
Authority* Fungus \for spcediiieibet: 
23 | Phytophthora teas COnIGie oe eee eee i 
22 Cystopus candidus, conidiasc. i. 6... eres es 2-10 
40 Plasmopara viticola, niet pe ae oe) ate es 3-12 
37 Venturia inaequalis, ascospores................ 4 
41 Guignardia Bidwellii, ascospores............... 36 
13 Endothia parasitica, ascospores...............-. 6-12 
39 Didymellina Iridis, sheen eintegemigea eS 18-36 
SCOSPOLeS. 256 FS SEE Cees 6 
5 Pseudopeziza Trifolii ‘asain See Pe re. aca 12 
42 Diplocarpon Rosae, conidia. ........ 6.252. 05 ess 24 
38 Glomerella rufomaculans, — fg et as ee 6-24 
43 Tilletia foetens, chlamydospores................ 48 
43 Ustilago Hordei, chia paidonpores A > aera gieseael 6.5 
43 Ustilago Tritici, chlamydospores............... 14-15 
25 Cronarti bicola, aectospores .<.. 5220025... 8-10 
25 Puccinia Antirrhini, urediniospores............. 5-8 
46 P. Phliet-pratensis, uri ‘sees ODORCS es pre as hoa, 3 
35 P. Malvacearum, teliospores................... 3 
9 ae Peaibet died telio- 
Pr Orc brs OF eee Pee Pir ak Te Pees 3-4 
30 Calettrich SCRA oi BS 10-24 
45 MNF oi bok ik cemkn im ee pe ee E 16-24 
32 Phllostct ANIME. oo ois coos ee es ees 16-30 
33 BNE sb veo Gen ies ce ee 18-24 
11 Cylindrocladium scoparium............02.0000% 2-3.5 
46 Depronna GOIN: be a ee 18 
sd Numbers refer to the literature cited. 
the respective optimum temperatures for germination. Other 
tests were made at temperatures approaching the minimum 
and maximum temperatures for the germination of the spores of 
these fungi. Under these conditions, in every case, a longer 
time v 1 for g tion than at optimum temperatures. 
Oxygen relation.—It was observed that spores in the interior 
of a drop of distilled water never germinated as well as those on 
