Article (magazine)  (1 Jun 2015)  Page(s) 282.  
 
Rosa subgen. Platyrhodon (R. roxburghii and R. praelucens Bijh.) is not resolved as monophyletic in our plastid analyses. While R. roxburghii is resolved as an independent lineage in both our plastid and nuclear analyses, R. praelucens is supported as a member of the Cinnamomeae clade in our plastid analyses. We consider the diploid R. roxburghii as a typical member of R. subgen. Platyrhodon. However, because allopolyploids have often been reported in the genus (Joly and Bruneau, 2006; Joly et al., 2006; Mercure and Bruneau, 2008; Schanzer and Kutlunina, 2010), we suspect that the decaploid R. praelucens (Jian et al., 2010) is an allopolyploid resulting from a hybridization event (or multiple hybridization events) involving the diploid R. roxburghii and at least one member of the Cinnamomeae clade. Based on karyomorphology, Jian et al. (2010) also suggested that R. praelucens is of allopolyploid origin, and a study in progress using GAPDH sequences supports the same conclusion (X. F. Gao, Chengdu Institute of Biology, CAS, Chengdu, China, pers. commun.).
....In the genus Rosa, hybridity is often accompanied by polyploidy and it may have helped stabilize hybrids between distantly related species of the genus. Polyploidy may also have favoured the rate of diversification (R. sect. Caninae), an increase in the geographic range (R. acicularis, R. spinosissima) and the colonization of high-altitude habitats (R. praelucens) or of high latitudes (R. acicularis).
 

Magazine  (2010)  Page(s) 162-167.  
 
In Caryologia (2010) 63(2), from the abstract:
Genus Rosa (Rosaceae) has a base chromosome number of x = 7. Ploidy levels of wild species range from 2n=2x=14 to 2n=8x=56. In this paper, one decaploid, the highest naturally occurring ploidy ever reported in the genus, was detected in the karyological study of an endemic wild species, R. praelucens Byhouwer to Zhongdian Plateau, Yunnan, China.... According to its karyomorphology, R. praelucens derived not from auto polyploidization directly but from inter-specific hybridization. Polyploidization associated with the effect of high altitude environment and inter-species hybridization both might have played important roles in the origin of R. praelucens.
at p.162 ff:
R. praelucens Byhouwer, first nominated by BYHOUWER (1929), was collected from Zhongdian Plateau, Yunnan, China by Forrest in 1914. It has ... the following characters: styles free and short, stipules adnate and not laciniate, flowers solitary, receptaculum armed and depressed-globose (BYHOUWER 1929). Owing to its large and showy flower with diameter to 15 cm and pink flower color when full blooming, it arose much interest of horticulturist...
Zhongdian Plateau lies in the south-eastern edge of Himalaya range, with an average altitude of 3400 m. 14 species of the genus Rosa were recorded in this area... The plants were grafted from buds of wild R. praelucens plants, which were located at an altitude of 3231m [10,600 ft]...Shoot tips were collected from the plants showing vigorous growth....measurements of chromosome arms were taken from at least ten well-spread metaphases of five shoot tips....The metaphase separation ... of R. praelucens clearly showed that it had 70 chromosomes.

Article (website)  (2008)  
 
R. praelucens Bijhouwer
collection: George Forrest, 1914, Yunnan

Article (misc)  (2007)  Page(s) 354.  Includes photo(s).
 
[Contains two photos. Figure 4 shows the basal shoots of a very old plant surrounding the cut stump of the original plant] R. praelucens, distributed in Shangrila county, Yunnan province. The main stem, over 42 cm in diameter, was cut in 1966, but the basal shoots from the main stem
are over 10cm. It is maybe the oldest plant among the upright shrub forms in rose genus all over the world.
[Figure 5 is a photo of the bloom] The flower of R. praelucens, may be the largest bloom in wild roses all over the world. It is distributed in Zhongdian (named Shangrila County now), the holy district praised by James Hilton in his well-known novel Lost Horizon.

Book  (2007)  Page(s) Database.  
 
R. praelucens Byhouwer Species, light pink, includes description.

Book  (1 May 2003)  Includes photo(s).
 
Rosa praelucens Byhouwer 中甸刺玫 zhong dian ci mei [with line drawing]
Shrubs 2–3 m tall. Branchlets purple-brown, ... robust; prickles few... robust. Leaves including petiole 5–13(–20) cm; stipules ... both surfaces pubescent... leaflets 7–13..., both surfaces densely puberulous... Flower solitary, (5–)8–9 cm in diam..... Sepals... slightly shorter than petals... leaflike... margin entire. Petals 5, red...Hip green-brown, depressed-globose, 1–1.5 cm in diam., sparsely glandular prickly, with persistent, erect sepals. Fl. Jun–Jul.
...NW Yunnan...

Magazine  (1929)  Page(s) 97-98.  
 
in J. T. P. Byhouwer, "An Enumeration of the Roses of Yunnan," Journal of the Arnold Arboretum, Vol. 10 (1929), 84-104

Rosa praelucens, spec. nov.
Frutex; rami crassi, glabri, annotini purpureo-brunnei, aculeis conformibus sparsis magnis 1-1.5 cm. longis basi dilatatis fuscis muniti; ramuli inermes. Folia 7-13 foliolata, petiolo incluso 5-13 vel ad 20 cm. longa; foliola obovata, obovato-elliptica vel ovalia, 1.4-2 vel ad 6 cm. longa et 0.8-1.2 vel ad 2.3 cm. lata, apice rotundata, basi rotundata vel obliqua, grosse simpliciter vel indistincte duplicato-serrata dentibus glandulosulis, supra obscure viridia, puberula, subtus cinerea, villosa vel in foliis maturis puberula, nervis vix elevatis; petioli 2.5-4.5 cm. longi, tomentosuli; petioluli 1-2 mm. longi, villosuli; stipulae adnatae, satis anguste, 1-2 cm. longi, auriculis divergentibus 5-8 mm. longis triangularibus vel lanceolatis, margine glanduloso-dentatis. Flores solitarii rubri, 8 cm. diam.; bracteae foliaceae, latae; pedicelli crassi, 6 cm. longi, glabri vel tenuiter tomentelli et interdum sparse stipitato-glandulosi; receptaculum depresso-globosum, glabrum vel laxe villosum, stipitato-glandulosum et ieviter aculeolatum; sepala ovato-lanceolata, petalis paullo breviora, basim versus margine glanduloso-denticulata, apicem versus foliacea, serrata, utrinque dense villosa vel extus basin versus glabrescentia; petala late obovata, 4.5 cm. longa, rotundata vel emarginata, extus glabra; stamina numerosa; capitulum stigmatum sessile. Fructus depresso-globosus, basi truncatus, viridis vel brunneus, sparse aculeolatus, sepalis erectis persistentibus coronatus, sine calyce 1.8 cm. diam., 1.4 cm, longus.

Open situations amongst scrub, Chungtien plateau, lat. 27° 30' N., alt. 2700-3000 m., G. Forrest, no. 12996 (type), July 1914 (shrub of 1.2-1.8 m., flowers fragrant, deep rose-pink) (E.); without precise locality, G. Forrest, nos. 16548 & 16936 in 1917-1919.

This beautiful large-flowered rose belongs in the section Microphyllae Crep., as it agrees in the characters; styles free, short, stipules adnate, not laciniate, narrow, flowers solitary, receptaculum armed, depressed-globose. It is easily distinguished from R. Roxburghii Tratt, which has shorter, strongly pinnate sepals, a more prickly receptacle and fruit, often more numerous and smaller leaflets and which lacks the velvety pubescense of R. praelucens. In the shape of the receptacle, the size of the flower, the hairiness and appearance of the leaves this new species recalls R. rugosa Thunb., probably it forms a link between this species and its allies of the section Cinnamomeae DC. and the heretofore isolated R. Roxburghii Tratt. Forrest's nos. 16548 and 16936 agree well with the type except that the leaves are larger; in the type the leaves are 5-8 cm. long and the leaflets 1-2.5 cm. long and 6-1.4 cm. broad, while in the cotype the leaves are up to 20 cm. long and the leaflets up to 5.5 cm. long and to 2.3 cm. broad.