Article (magazine)  (2001)  
 
KEY TO VARIETIES
1. Shrub more than 1 m tall (usually up to c. 1.8 m):...... 1. var. delavayi
1. Shrub or subshrub up to not more than 1 m tall:..... 2. var. angustiloba

1. var. delavayi
KEY TO FORMAS
1. Petals entirely orange or yellow to greenish-yellow, or yellow blotched with dark red at the base, or yellow with a red margin:..... 1b. var. delavayi f. lutea

1b. var. delavayi f. lutea (Delavay ex. Franch.) S. G. Haw, stat. nov. Typus: China, NW Yunnan, Eryuan County, Mt Hea Chan Men, 25 May 1883, Delavay s.n. (lectotype, P - n.v., isolectotype, K); Syn. P. lutea Delavay ex Franch., Bull. Soc. Bot. Fr. 33: 382 (1886)....Included here are all the taller-growing variants of the species with predominantly yellow or orange flowers. Orange-flowered plants may be the result of hybridisation between plants with yellow and red flowers and their inclusion here is therefore more or less arbitrary. P. delavayi var. lutea of gardens belongs here. As far as I can ascertain, there is no clear record of white-flowered plants tall enough to be placed with this variety.

Book  (Jan 2000)  Page(s) 49-50.  
 
Stern's second subsection of tree peonies, subsection Delavayanae, includes several species discovered in the mountains of Southwestern China toward the end of the 19th century. In it, he identified and defined the following species:
....Paeonia lutea Delavayi ex Franchet var. lutea
This is a native of Yunnan province, most abundant in the mountains above Dali. It differs from previous species in the color of its flowers, which are a clear lemon-yellow. It varies greatly in size over the range where it has been found, from 3 feet to more than 6 feet in height. The small flowers, 2-3 inches in diameter, are usually hidden by the foliage. Once gain, the species has no real landscape value, but its appealing lemonlike fragrance is often passed on to its hybrid offspring. Hardy to zone 5, though it seldom blooms in climates colder than zones 7 or 8; even then it is sparsely floriferous at best. Diploid (10 chromosomes).

Book  (Jan 2000)  Page(s) 21, 22.  Includes photo(s).

Book  (Jan 1999)  Page(s) 632.  Includes photo(s).
 
P. lutea ('Yellow Tree Peony') from western China... introduced to the West in the late nineteenth century

Book  (Jan 1999)  Page(s) 19.  
 
Paeonia lutea another of Père Delavay's 1884 discoveries, found on Mount Hea Chan Men in Yunnan and in the mountains above Dali at overlapping and slightly higher altitudes than P. delavayi. The plants are similar in some ways, and may be two forms of the same species. They can never be confused when in flower, for P. lutea lives up to its name with single flowers of bright, clear yellow. They have the bonus of a lemony scent but they share with P. delavayi a reluctance to flower in climates below Zone 7.

Book  (1999)  Page(s) 137.  
 
Paeonia lutea, China, Tibet, 1949

Magazine  (1901)  Page(s) tab 7788.  Includes photo(s).
 
Paeonia lutea. Native of China. ...Franch....