Magazine  (Sep 1977)  Page(s) 23.  
 
"Botanical Descriptions of 40 Saunders Lutea Hybrids" by Dr. David Reath and Silvia Saunders
...These descriptions aim to provide the nurseryman and the average gardener with a means of determining the differences between the hybrids, many of which are very similar indeed...
Wings of the Morning—Single; 10 petals, palest yellow, of heavy substance. Furled back. Flares wide and dark; dramatic. Filaments creamy reddish. Stigmas cream-white, sheath cream-white. Anthers uneven lengths. Foliage of heavy substance.

Website/Catalog  (1960)  Page(s) 14.  
 
Tree Peony Hybrids or Lutea Hybrids
Crosses of the Japanese Tree Peony (P. moutan or suffruticosa) onto P. lutea or P. Delavayi. These bloom through the first half of June, sometimes longer. [...]
Because these hybrids fall rather naturally into a few large color groups, I have listed them by color, with the suggestion that when ordering, you either specify a group number only, or allow me some latitude in substituting. [...]
1. The "Roman Gold" Group.
Yellow, clear or almost clear. Generally single.
Wings of the Morning  Pale large flowers with greenish tones; flared dark. Petals crinkled.

Article (magazine)  (Jan 1955)  Page(s) 24.  
 
Varieties Raised in America. All by Professor Saunders...
The "Roman Gold Group." Yellow, clear or almost clear , generally single.
'Wings of the Morning,' (1948), formerly Aureole

Magazine  (Mar 1954)  Page(s) 22.  
 
Hybrid Tree Peonies
...By far the most important work with these hybrids has been done by Prof. A. P. Saunders and his originations now number about 80. Their color range is truly remarkable. [...]
The list of hybrid tree peonies following is up to date as far as we could make it.
Originations of A. P. Saunders, Clinton, N.Y.
Hybrids of suggruticosa, lutea and Delavayi.
Wings of the Morning, Single, pale yellow, purple flares. 1948.