348 
Report oF THE HoRTICULTURIST OF THE 
on apple, pear, and quince fruits when inoculated with cultures of 
Sphaeropsis from the different hosts. 
TABLE I.— SpoRE MEASUREMENTS OF SPHZZROPSES FROM DIFFERENT SOURCES 
AND ON DIFFERENT HOSTS. 





Zi SSSR Bese Bese 
“aS agoee HyonE gore 
O65 Conese Cokes Meet 
Gh as as SS naa ag aa 
~~ O os NHS ~~ Sw eS = nes 
: ways MeL oD 8 ws B 
Hosts from which cultures of Spherorsis sem ASS90 Peete ALEK 
were obtained. Leo Vaasa Leased "Sse 
eS neal Se Ee HED 
O82 S&S2cqH SSoacu HS 
S52 soa0ke S5888, e5958% 
Qa3n°9 Seno O2Oo go 
ORS Saesha Shosk5 Saasas 
<j < < < 
Rear GREG LE WISH oat panko ace pat ee oe 22 30 29 
Quince’ treelimbs: 270 P. i Pee 23 29 29 
Appletree limbs 2. eo: the ee 26 29 30 
Japanese plum, Prunus triflora, Roxb. 28 30 30 
Hawthorn, Crategus oxyacantha, L.. 21 28 
Persimmon, Diospyros virginiana, L.. 21 28 
Wild crab, Pyrus coronaria, L....... 21 28 
Sumach, Rhus typhina, [on s.:) .s.%s 23 29 
Bitter sweet, Celastrus scandens, L.. 22 - 
Apricot, Prunus armeniaca, L....... 22 30 
Choke cherry, Prunus virginiana, L.. 21 29 oe 
Hop horn beam, Ostrya virginica, 
Willd., decorticated wood ......... as 28 
Mulberry, ‘Morugialba,s b See: oan 21 it 
European plum, Prunus domestica, L. 21 25 
Elder, Sambucus canadensis, L....... 21 29 af e 
Pear Wea Wee so) os aes Se ace ae 24 30 ius 



The table is of interest in that it shows that the average size of 
spores of Sphacropsis varies according to the host on which they 
are grown. Jor instance the pycnidia and spores as they grow 
on pear wood are somewhat smaller than those that are found on 
apple wood, yet the spores produced on apple fruits inoculated | 
with cultures from either host, are of the same size and character ; 
similarly, though not shown in the table, when pear trees 
are inoculated with cultures of Sphaeropsis taken from apple trees 
the resulting pycnidia and spores are of the average size of those 
found in nature on pear tree bark. 
The spore measurements also show that in most cases there is 
but little difference in the average size of the spores of Sphaeropses 
