Sometimes "seed" stitch is called "moss" although they are technically based on different row multiples.
There are many kinds of chevrons but the basic idea is that the reversed knit and purl stitches form a vee pattern as the fabric is being knit.
One version of each of these patterns is found at:
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www.knittingonthenet.com]
Check closely to see if your source is actually talking about "moss" or "seed."
If you want to further investigate these stitches and the chevron's many possibilities check to see if Barbara Walker's first Treasury of Knitting Patterns or any of the other many stitch bibles are at your local library. Reader's Digest has a fairly new, very useful compendium of knit and crochet pattern stitches.
By the way all of these stitches are very useful because they are reversible and form fabrics that will lie flat and not curl at the edges. They make particularly good scarves for that reason.