aravah/willow

I am actually looking for the full scietific name for the kosher aravah used on sukkot. Willow there are hundreds of types of willows, some are trees, others are bushes. even in the bushes family, there are so many different kinds, which one/ones are kosher? can i just use any kind that's in the Salix family as long as it looks like the aravot i am used to seeing? thank you,

Dear Hillel: The halakhic sources are not specific enough to allow an identification of the scientific name of the aravah used on Sukkot. Scholars identify the biblical aravah with salix Alba (white willow). Rambam describes the willow used on Sukkot as follows: "Its leaf is long and smooth and its stem is red." Nevertheless, a brown or green stemmed willow is also permitted for use on Sukkot.