Medieval poetry

[zrugui]

I am doing a commentary about a medieval poem "lenten ys come". I cannot understand the double meaning of some words. Would you help me finding them or tell me the web site where I can find them.
These words are: "nighting gale, thrush, daisies, woodruff, fennel, thyme, worm".
I ask myself if these birds or plants had a double meaning in that age.
Thanks a lot in advance

[Tdol]

Animals often were used symbolically. Here's a modern translation of a medieval Bestiar, which might help:
http://digicoll.library.wisc.edu/His...aryAbout.shtml