I received a comment on my essay saying these two are not examples of alliteration. Are they or are they not?

"Winter was a weird time for the world,"
and
"I was walking in the woods, when I noticed the trees were filled with branches of only DULL GREEN."

Thanks.

The first sentence includes alliteration — w ... w ... w ...

It would be better if those w-words were closer together in the sentence, but still the alliteration is there. The first part of the second sentence, too, has a brief touch — walking and woods.

“Dull green” is not alliteration, though!