The half-elf has unique racial traits, but one of those racial traits is elven blood, which says
For all effects related to race, a half-elf is considered an elf.
Half-elves aren't available as ranger's favored enemy and aren't given a unique entry in the Monster Manual, sharing the entry with elves, leaving the half-elf subtype suspiciously unmentioned.
In technical Dungeons and Dragons 3.5 terms, are half-elves themselves a race? Are half-elves a kind of elf? Further, do half-elves possess the elf subtype, the human subtype, both, or neither?
I was organizing a list of feats based on their availability, attempting to do so using the taxonomy of (from largest to smallest) of race, kind, type, and subtype, but got stumped by the half-elf, who can, apparently, meet the prerequisites of elf feats (as per the racial trait elven blood) yet can't, for example, meet the prerequisite of star elf feats (of which, I think, there are but two). Disabusing me of my notions about D&D 3.5 taxonomy is a valid answer to this question.