Website/Catalog  (1960)  Page(s) 15.  
 
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. [...]
3. The "Tea Rose" Group.
Generally yellow, but tinted and suffused rose. Single to double. 
Apricot  Like its name; dusky rose tones. Silver-grey fern-like foliage. Flowers held high.

Article (magazine)  (Jan 1955)  Page(s) 25.  
 
Varieties Raised in America. All by Professor Saunders...
The "Tea Rose Group." Generally yellow, but tinted or suffused reddish, single to double...
'Apricot,' (1948-1950)

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, Yellow with reddish tones, 'Apricot', (Saund. 1948-1950), [Gardens] Morton Arboretum, Scott Foundation

Magazine  (Mar 1954)  Page(s) 21.  
 
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.
Apricot, Single, rose and yellow. 1948.