The foliage is typical of L. formosanum with narrow leaves that are significantly longer at the bottom of the stem and tapering to much shorter towards the top. The shape of the buds certainly look more L. longiflorum-ish (kind of poofing out in the middle) but I don't think L. longiflorum leaves are that narrow.
L. longiflorum and L. formosanum are two different species. L. formosanum actually grows like a weed, easily reseeding in some places (e.g.,Taiwan).
You may find names for this lily that involve "longiflorum", "philippinense" and possibly others but they are synonyms.
