



A 



/\ 



B = 



Y 



A 



B 



A 



X 



C = 



Y 







B 



X 



D = 



Y 



C 



D 



C 



X 



D = 



Y 







D 



X 



A = 



Y 



B 



A 



C 



X 



B = 



Y 







A 



X 



B = 



Y 







A 



X 



B 





N 



A 



B 



A 



X 



C 





N 







B 



X 



D 





N 



C 



D 



C 



X 



D 





N 







D 



X 



A 





K 



B 



A 



C 



X 



B 





N 







A 



X 



B 





N 







A 



X 



B = 



Y 



A 



B 



A 



X 



C = 



N 







B 



X 



D = 



Y 



C 



D 



C 



X 



D = 



N 







D 



X 



A = 



Y 



B 



A 



C 



X 



B = 



N 







A 



X 



B = 



Y 







A 



X 



B -- 



= Y 



A 



B 



A 



X 



C = 



= N 







B 



X 



D : 



= N 



C 



D 



C 



X 



D : 



= Y 







D 



X 



A : 



-- N 



3 



A 



C 



X 



B : 



= N 







A 



X 



B : 



: Y 



TWO CLONES: A + B; C + D 



Figure 1— Sample illustrations of pattern of isolate 

 challenges used to delineate clones of the genus 

 Armillaria found on National Forests of the 

 Northern Rocky Mountains. 



be stable diploids (Korhonen 1978). The plates were in- 

 cubated under room conditions for 21 to 30 days prior to 

 reading and recording results. Each challenge was repli- 

 cated three times to produce a single evaluation (read). 

 Each of us independently assessed the three replications 

 to record a summation of "yes" (compatible) or "no" (non- 

 compatible). The three replications were judged "yes" if 

 the challenge mates grew freely together and "no" if they 

 failed to grow together, as shown by a line of demarca- 

 tion, a free space, or a line resulting from mycelium 



crowding. A crowd line is formed when the challengers 

 push against each other but appear not to join and they do 

 not form a brown line of demarcation. Genetically identical 

 mycelia are thought to freely grow together (Korhonen 

 1978). Relationships between isolates that failed to grow 

 together could range from parents and sibs with identical 

 compatibility alleles but otherwise different genomes to 

 species that belong to different intersterility groups 

 (Korhonen 1978). 



2 



