20 BULLETIN 727, U. S. DEPARTMENT OF AGRICULTURE. 
tilled water inoculated with spores and incubated at thirteen different 
temperatures between 3° and 31° C. secured in an Altmann compart- 
ment incubator and in other constant-temperature incubators. The 
results are presented in Table II. 
TaBLeE II.—Relation of temperature, oxygen supply, and food supply to spore germination 
and appressorium formation of Colletotrichum lagenarium. 
[Abbreviations: ab = abundant, ap = appressoria, d = day or days, g = germination, gt = germ tubes, 
hr = hours, mar = marginal, num = numerous, pe = per cent, spo = sporulation, sw = swelling, tg = 
trace of germination.] 
Distilled water. Prune decoction. 
eh NS wi Ye) hz oa ete tek ce SE ORR Cant ere Set ewe Rut che aoe ae 
ture (C.). | 
Hanging drop. Exposed drop. Hanging drop. | Exposed drop. 
QAO cae ae | SLOGAN Ole cee eae LOVE OMe nee [LO nowt e ee ees | 19d, some swollen. 
BTC sees [eae eae Ree tee ge IMIG Os Se Seas HOG Ope ees asec | 7 d, sw; 19 d, a few 
short gt. 
6atow see elOidean ors LGid is was|cond, nore: a aswel Os e1Oldeimo) eee meses IPG To) ee Ol. es Gi. 
d, a few budlike num short gt; 7 d, 
gt. 0 pe short budlike 
; gt. 
OSstonlOcnaesl teins = AL Aes nls eh SiG noes Ode oud=9) Odean Oye seer 1 d,no g; 2 d,3 peg; 
ding gt. 7 d, 90 pe g, short gt, 
| ap ab. 
11° +0 12°...) 2d,sw; 10d,nog...-) 2d, 10 peg; 3d,ap | 2 d, sw; 10 d; sw,.| 10 hr; tg; 1d) 1 peg, 
| ab; 5d, 80peg. no gt. | short gt; 2 d, 90 pe 
g; 3d, ap general. 
TSO oy TR eer esertee re e ohee 1 d, 1 pe short slen-| 1d,no g; 2d, swollen | 10 hr, tg; 1 d, 5 pe g; 
| | der gt;2d,10pce| (septate); 7 d, 95|, 2d, a few ap; 10d, 
| g, ap present. pe pee: 5 pe nor- acervuli spo. 
| mal g. 
Hea Y sch = | 1d,no g; 2d,5 peg; | 1d, tg; 2d, 90 pe g, | 2d,nog(cellfoundair | 1 d, 20 pc g, gt robust; 
| 5d, ap formed. ap Dum (mar). tight); 5d, nog. 2 d, 90 pe g, a few 
| ap; 5 d, ap num, 
acervuli forming. 
Tee eat Renee Sette eae See | 9 hr, 1 spore germi- | 1d,1 pcg; 2d, opcg, | 9 hr, tg; 1 d,5 pe g,ap 
| nating; 1d,5 pcg, long gt; 3 d, no ap; present (mar); 2 d, 
afew ap. 7 d, acervuli; 10 d, ap. num; 7 d, spo. 
spo. 
ISP ROTO Ssell BGl ioe. osseoscacac 1d, 20 pe g, ap pres- | 11 hr, 2 spores germi- | 9 hr, 1 pe g; 1 d, 40 
| ent; 2 d, ap num nating; 1 d, 1 pe g; pe g, ap present; 3 
(mar). 2d, 3 pe g, ap pres- d, ap num; 7 d, spo. 
ent; 4 d, acervuli 
forming; 5 d; no 
spo. 
18° to 20°..-| 10 hr, 2 pe g; 1d, 10 | 10 hr, 1 spore germi- | 1d, 90 pe g;’2d,noap; | 9 hr, 3 pe g; 1d, 10 pe 
pe g; 3d, noap; 4 nating; 1 d, 5 to 3d, ap num. g, ap present (mar); 
d, ap num. 10 pe g, ap Dum 3d, acervuli forming; 
(mar);2> d;- 10 4d, spo. 
pe g. 
De ie tee O88 8i hr, 5 pe g; 1d.20| 1 d, ab g, ap pres-| 1d, 90 pe g; 4 d, spo, | 8hr, 10 pe g; 1d, 20 pe 
pe g, gt slender, ent; 2d, ap num no ap. g; 2d, ap; 4d,spo. 
afew ap (mar); 2 (mar). 
d, ap num. 
263° to 274°.| 10 hr, 20 pe g; 1d, | 8 hr, 10 pe g,14d, 25 | 10 hr, sw; 1d, 95 pe g; | 8hr, 10 to 20 pe g; 1d, 
30 pe g;.3d, afew pe g, ap (mar); 5d,noap; 7d, spo. 75 pe g; 2d, ap pres- 
long-stalked ap. 2d, ap num. ent: 4d, spo. 
30° to31°.-..| 93 hr, lateral bud- | 8 hr, tg; 1d, 5 pe g; | 9hr,sw; 20hr, 95 peg; | 8 hr, 10 to 20 pe g; 1d, 
like gt; 20 hr, 40 4 d,50peg; 5d,no 2 d, extreme sw of 95 pe g, colonies visi- 
pe g; 38 d ex- ap. spores and myce- ble to unaided eye, 
tremely swollen lium; 3 d, no ap. no ap; 5d, noap, no 
budded spores or darkening. 
‘involution 
forms’’; no ap. 
AG GSELT. sano. ~ Soc eee INO Gosh sake tenes Shh asin. season No g. 
——— 
More vigorous germination was obtained in prune decoction than 
in water, and in either medium the exposed drops furnished better con- 
ditions for germination than the hanging drops. The latter is 
attributed to lack of aeration in the Van Tieghem cells, although, in 
preparing these, care was exercised not to have the vaseline seal con- 
tinuous around the edge of the rmg. At the rather high tempera- 
