The identifier of this plant was German. His name would have been pronounced in his own tongue - "VI-gel." Now you throw in that plant nomenclature is in Latin and you have an immediate problem. To my knowledge , there is no "W" in Latin, but there is certainly a "V" - "Veni, vidi, vici." (Having said that, my father learned it as pronounced "Weni, widi, wici." I learned it with the "v" substituted for the "w.") Confused enough about a language so dead there is no one to assure us as to its correct pronunciation? If we look at the simple phrase we all, who had to study Latin, know "Gallia est omnis divisa in partes tres," then the proper pronunciation is either "ViGELa" or "WiGELa." The "G" is hard and the accent is on the second syllable and there is no "i" in the third. I doubt we've solved the world's problems with this exercise...
Classical Latin is fairly straight forward in its pronunciation. Each vowel is pronounced and constitutes a syllable. The familiar ones are: a, e, i, o,u. Latin also has 'blended vowels' known as dipthongs. ae, au, ei, oe, ui which are pronounced with a single sound. Example: the dipthong 'ae' is pronounced as the word 'eye' in English. In older books these dipthongs were printed as two letters stuck together for easy recognition. Understand that Latin's long and short vowels do not follow the English pronunciation. Example: long a in Latin sounds like the a in 'father' not 'fate'.
All consonents have hard sounds. C as in cat, (k sound), not as in center. G as in go.
R was always trilled or rolled like Spanish.
Ok, so here's the 'gotcha'. Many names of plants commemorate a person. Botanists from all over the world name plants and each personal name is pronounced according to their own language just as omasuzig has stated. William Stern, the author of Botanical Latin, say the attempt should be 'euphonious'. Do the best you can! (Former Latin teacher)
P.S. The book mentioned above is great. Also consult Wheelock's Latin. Clear explanations, seminal text of past generations.
It was fund hearing all the replies. I, too, took Latin years ago. Mostly though, I think of Volkswagen as I pronounce it, which not many people do. Folksvagen. No, the world's problems are solved by pronunciations, but it's also fun.