According to The Hostapedia by Mark Zilis (2009), "H. 'White Beauty' = H. 'Undulata Albomarginata'

Another source indicates that Jan van den Top of the Netherlands originated this non-registered cultivar in 2002 and it is a sport of H. 'Undulata Albomarginata'.  This medium size (18 inches high by 36 inches wide) plant has pale lavender flowers with a mid-petal stripe in July. The flowers are sterile so they do not develop seeds.

An article about H. 'Undulata' and its origins by Bob Solberg in The Hosta Journal (1996 Vol. 27 No. 1) states that, "H. 'Undulata Albomarginata' is an interspecific hybrid of H. sieboldii x H. montana but of different individual parentage than H. 'Undulata'. It was probably sold to Thomas Hogg in 1875 in Yokohama, Japan. It is not a sport of H. 'Undulata' or H. 'Undulata Erromena', the white-edged sport of the latter being H. 'See Saw'...While the data presented here strongly support these conclusions, they do not provide absolute proof. DNA testing of these cultivars would prove very interesting."