Newsletter  (Sep 2018)  Page(s) 15. No. 18.  
 
Peter D. A. Boyd. Scots Roses And Related Cultivars Of Rosa Spinossima.
....and the rose described by Thomas is probably ‘Bicolor’, as illustrated by Andrews (1822)....

Article (magazine)  (2008)  Page(s) 24.  Includes photo(s).
 
Bicolor was a name applied in the early 19th century to a semi-double Scots rose that was bicoloured in the same sense as R. foetida 'Bicolor', but the petals are purple on the front and white on the back (see also Mary Queen of Scots). There are cultivars given the name today that are very different, with pink markings on white petals. The old meaning of the name should have priority.

Book  (2001)  Page(s) 223.  
 
Pimpinellifolias
1803: 'King of Scots'

Book  (Apr 1999)  Page(s) 183.  
 
King of Scotland ('Bicolor', 'King of Scots', 'King of the Scotch', 'Large Double Two-Coloured', 'Roi d'Écosse') Pimpinellifolia. R. Brown 1803. The author cites information from different sources... Red... rosy purple... currant red...

Book  (Apr 1999)  Page(s) 181.  
 
Bicolor Pimpinellifolia. Breeder unknown, pre-1846. Possibly 'Bicolor Nana'... Otherwise, listed in 1846 without description...

Book  (1978)  Page(s) 209.  
 
'Bicolor' Short Pink & white Late spring
It is possible, though not certain, that this is one of the earliest Scotch Roses, for a list in 1822 refers the 'Large Double Two-Coloured Scotch Rose' to R. spinosissima bicolor; Modern Roses 7 refers the varieties 'Grahamstown' and 'Staffa' here, so the message seems to be, when in doubt call it bicolor; there has been much doubt in identifying Scotch Roses.

Book  (1954)  Page(s) 186.  
 
King of Scots (Lee) - Moderate Growth. Double deep pink flowers.

Book  (1936)  Page(s) 88.  
 
Large Two-Coloured. Semi-double, like 'Two-Coloured Scotch', but larger. Figured by Andrews as 'bicolor'.

Book  (1936)  Page(s) 655.  
 
Scotch, King of the (Pimpinellifolia) in Scotland ? ; currant and greyish white, medium size, double

Book  (1903)  Page(s) 236.  
 
Rosa spinosissima.  The Scotch Rose.
9.  King of Scots, flowers pink.