There are principally two +/- correct ways to pronounce scientific
plant names.
The first is classical Latin. This has the advantage of philological
"correctness" (scientific names are to be treated as if they were
Latin, according to the ICBN) but at the same time it has several
disadvantages:
1. Latin is not a "living" language, so nobody is really a native
speaker. The modern derivatives of Latin, i.e. Italian, Spanish,
Portuguese, French, Romanian, and several others all have their own
pronounciations which have only little or nothing at all in common
with classical Latin. The classical pronounciation can only be
deduced from painstaking analyses of ancient Roman poetry or the
rather few (I do not know a single one but there may be some)
authentic linguistic works.
2. Latin is in itself a collection of various dialects which has
developed during the existence of the Roman Empire.
3. The Latin used in Botany is in fact derived from medieval Latin
(the starting point of botanical nomenclature is 1753), i.e. an
unnatural "modern" dialect developed by scientists, clergymen and
lawyers while the original Language (used in real life by normal
people) was gradually replaced by what is now called Italian or the
Romance languages (which Fernando calls "Latin languages").
4. Some epithets (based on names of persons or places which do not
have a classical Latin name) cannot be pronounced at all in classical
Latin without severe damage to the tongue of the person who tries to
do so (e.g. _champagneuxii_, _przewalskii_, _walyunga_, etc.).
The second way is to pronounce the names as if they were items of the
language of the respective speaker. This has the advantage that it
is, e.g. in Italian (naturally), French (at least mostly), German
(frequently), Czech (nearly always), etc. not difficult to find the
individually "correct" way (despite problems to find the correct
syllable to stress). However, there are serious disadvantages:
1. Foreigners will in all probability not understand at all what is
meant.
2. The virtual absence of rules of English pronounciation, especially
if loanwords are concerned. Or worse, there are too many such rules
competing each other, depending on the person asked: _Pisum sativum_
is pronounced like "Pyesome saytyevome" by one speaker and like
"Peesoum suteevoum" by another, both native to the British Isles (and
both not illiterate in terms of nomenclature). This is in fact
reminiscent of Arabian or Hebrew (BTW shalom Dr. Joel, nice to have
you here!), where the vowels are likewise +/- a matter of taste, the
compromise only settling on consonants (the strict consensus between
both speakers being P*s*m s*t*v*m, *=any vowel considered
appropriate). Even species are controversial (not only in
circumscription but also in pronounciation). For some they are
"speechious", for others "speetseeas". And please note that I was not
talking about American English yet.
So I fear it is not at all trivial to define the single "correct"
pronounciation. My proposal: try feeding scientific plant names
(especially problematic ones as those cited above) to some
pronounciation software (e.g. "speak"). The output is nearly
always surprising (and lots of fun), and at least it demonstrates
problems where you would never have expected them!
Kind regards
Jan