Albert Barnes Commentary Exodus 16:31

"And the house of Israel called the name thereof Manna: and it was like coriander seed, white; and the taste of it was like wafers [made] with honey." — Exodus 16:31 (ASV)

manna—It was not indeed the common manna, as they then seem to have believed, but the properties which are noted in this passage are common to it and the natural product: in size, form, and color, it resembled the seed of the white coriander, a small, round grain of a whitish or yellowish-grey.