Book  (2010)  Page(s) 242.  
 
Hybrid nothospecies....Paeonia yananensis T. Hong & M. R. Li (pro sp.), Bull. Bot. Res. (Harbin) 12(3): 226, fig. 3 (1992)....We have visited the herbarium CAF, but the curator could not be able to find "the type T. Hong 915013". The senior author, T. Hong, subsequently told us that he failed to preserve the type. Paeonia yananensis is morphologically intermediate between P. rockii subsp. atava and P. jishanensis, which are considered the two putative parents of the hybrid....This consideration has been confirmed by sequencing of the single-copy nuclear gene...Additional specimens examined. China, Shaanxi, Yan'an...

Article (magazine)  (2001)  
 
Although the flowers of P. yananensis and P. papaveracea show considerable similarity, there are very clear differences in the leaves. Those of P. yananensis often have 11-15 leaflets, while those of P. papaveracea never have more than nine. The shape of the leaflets is also different. The foliage of P. papaveracea is absolutely typical of P. suffruticosa, closely similar to that of most P. suffruticosa cultivars. It does not, therefore, seem reasonable to consider these two taxa identical. P. yananensis is probably the result of hybridisation only between P. rockii and P. spontanea, while P. papaveracea is a cultivar of P. suffruticosa, a complex hybrid with not only R rockii and P. spontanea but also P. ostii in the parentage

Paeonia X yananensis T. Hong & M. R. Li, pro sp., Bull. Bot. Res. 12 (3): 226, fig. 3 (1992). Typus: China, Shaanxi, Yan'an, Wanhua Shan, in Platycladus forest, 15 v 1991, T Hong 915013 (holotype, CAF .n.v.).....This taxon is intermediate in morphological characters between P. spontanea and P. rockii and is considered to be a hybrid between them. Both these species are present in the area where it was found. It has quite small flowers (10- 12 cm diam.) with white or pale purplish-rose petals with a dark purple basal blotch and deep purple disc. The leaves are quite similar to those of P. spontanea, but with narrower leaflets. D. Y Hong and K. Y Pan (1999) considered T. Hong and M. R. Li's species to be identical with Andrews' P. papaveracea. There are very obvious differences between the leaves, however: those of Andrews' P. papaveracea have no more than 9 leaflets with entire margins or few lobes (rarely more than 3), while those of Hong and Li's P. yananensis have up to 11 usually 3-lobed and toothed leaflets. P. yananensis also seems to be a much smaller shrub than P. papaveracea.

Book  (Jan 2000)  Page(s) 49.  
 
The four species described by Hong and his associates are as follows:
....Paeonia yananensis Hong and M. Li
An extremely rare plant, named for the district in Shaanxi Province in which it was found. It stands at just 16 inches and has few leaflets. The petals are white or pale purplish rose with a dark red basal blotch. The filaments, disc, and style are reddish purple. Diploid (10 chromosomes).

Book  (Jan 1999)  Page(s) 23.  
 
Paeonia yananensis from the arid hills of the Yan'an district of Shaanxi Province... The flowers are sometimes white, sometimes pale purplish rose with a dark red blotch at the base