It's interesting, this website and Wikipedia are clearly using the same information, but I can't tell what the source of that information is. Some of the meanings they have look like they're taken from Greenaway, although some are different. The reason I like the Greenaway source is that it's so extensive -- there is just about every meaning you can think of, unlike most recent sources that just give meanings for popular flowers. I remember being interested in a question someone asked on a message board about the possibility, in a story, of giving flowers as a declaration of war, and what flowers could symbolize that. No one could give a good answer because so many websites tend to just focus on normal florists-shop flowers. Well, with Greenaway you could do it -- give a bouquet of St Johns Wort (for "animosity"), gorse/whin (for "anger"), basil (for "hatred"), and yarrow (for "war") (all yellows and whites!). This is just ordinary floriography, though. In the context of the Dusk in which flowers are associated with death, and not normal gifts, that would actually seem to increase the chances of flowers being given as a declaration of war.
Sorry for rambling... I'm kind of crazy about plants. : P (Incidentally, I notice that you have 'Saxifrage' listed in the wiki...)