Article (magazine)  (Jan 1955)  Page(s) 25.  
 
Varieties Raised in America. All by Professor Saunders...
The "Black Pirate Group." Crimson to very dark, almost black maroon, single to double...
'Black Douglas,' (1948)

Article (magazine)  (Jan 1955)  Page(s) 56.  
 
Alphabetical Check List of Tree Peony Names In  Public Collections And/or Available in Nurseries 1954-1955
Lutea hybrid, Crimson, 'Black Douglas', (Saund. 1948), [Gardens] Morton Arboretum, Scott Foundation

Book  (1944)  Page(s) 104.  
 
For next year 1945
Make a master list of tree peonies to be grafted & check them off as done.
For 1944
...Black Douglas 3

Book  Page(s) 47.  
 
Typhoon #11994 [crossed out and replaced with Black Douglas 11995] Original plant in 16.2 L.D. x Hatsugarasu Very black double, fine. Extra quality (Burton 1440)..Double Black Pirate
1939 2 grafts in 8(10) 1 took
1941 Very impressive push
1941 1 salable graft in 8(10) now 6