I thought to check back to see if there were any later addenda or correspondence regarding this Lily, and I found the following letter written in response to the above article.
Looking ahead to 1921, I see that there is more correspondence of greater bulk, though I'm not less confused after looking it over. Hopefully, it will be less so for you lily cognoscenti.
And before I head off to Dreamland, here is a closer look at the photo from the original article:
