4 NATL. ARBORETUM CONTRIB. NO. 2, U.S. DEPT. AGR. 



or less in diameter. Both ornamental and economic plants are in- 

 cluded. 



Asterisk (*).. — An asterisk following a name of specific, varietal, 

 or cultivar rank indicates the plant did not result from a controlled 

 pollination and the parentage is, therefore, doubtful. In each case 

 where an asterisk does not appear following a name, it should not 

 be assumed, unless otherwise stated, that the plant resulted from 

 a controlled cross but that such evidence is lacking. 



Disease free (41). — This refers to the results of an 8-year 

 disease survey conducted by Lester P. Nichols, Pennsylvania State 

 University, University Park. During this period, Nichols rated 

 hundreds of crabapples for the following diseases : scab caused by 

 Venturia inaequalis (CKE.) Wint. ; cedar apple rust caused by 

 Gymno sporangium juniperi-virginianae Schw. ; powdery mildew 

 caused by Podosphaera leucotricha (Ell. & Ev.) Salm. ; and fire 

 blight caused by Erwinia amylovora (Burr.) Winslow. Those 

 crabapples Nichols found to be completely free of the above 

 diseases are noted. 



Key to Locations of Reported Documented 

 Crabapple Material of Authentic Origin 



(A) Alfred L. Boerner Botanical Gardens, 5879 South 92d Street, Hales 



Corner, Wisconsin 53130, U.S.A. 



(B) Arie den Boer Arboretum, Des Moines Water Works, 1003 Locust Street, 



Des Moines, Iowa 50309, U.S.A. 



(C) Arnold Arboretum, Jamaica Plam, Massachusetts 02130, U.S.A. 



(D) Arthur Hoyt Scott Horticultural Foundation, Swarthmore College, 



Swarthmore, Pennsylvania 19081, U.S.A. 



(E) Beal-Garfield Botanic Garden, Building A-l, South Campus, Michigan 



State University, East Lansing, Michigan 48823, U.S.A. 



(F) Brooklyn Botanic Garden and Arboretum, 1000 Washington Avenue, 



Brooklyn, New York 11225, U.S.A. 



(G) Callaway Gardens, Pine Mountain, Georgia 31822, U.S.A. 



(H) Dominion Arboretum and Botanic Garden, Central Experiment Station, 

 Ottawa, Canada. 



(I) Experimental Farm, Canada Department of Agriculture, Morden, Mani- 

 toba, Canada. 



(J) Highland and Durand-Eastman Parks, 5 Castle Park, Rochester, New 

 York 14620, U.S.A. 



(K) New York State Agricultural Experiment Station, Geneva, New York 

 14456, U.S.A. 



(L) Oregon State University, Corvallis, Oregon 97331, U.S.A. 



(M) Royal Botanical Gardens, Hamilton, Ontario, Canada. 



(N) The Holden Arboretum, Sperry Road, Mentor, Ohio 44060, U.S.A. 



(O) The Morton Arboretum, Lisle, Illinois 60532, U.S.A. 



(P) U.S. National Arboretum, Washington, D.C. 20002, U.S.A. 



(Q) U.S. Plant Introduction Station, Glenn Dale, Maryland 20769, U.S.A. 



