Baby parsnips vs. parsley root I cooked parsnips for the first time this week (glad I did - delicious).  When the produce clerk pointed them out, I asked if he had baby parsnips instead (as the recipe called for them).

He pointed out parsley root, which looked very similar.  I did a search while in the store (and got in many shoppers' way), but could not find whether they were the same thing definitively.

A follow up question would be, if they aren't in fact the same thing, had I chosen to make this dish (roast veggies and chicken), how would the taste have differed for the parsley roots?
Parsley root is not the same as parsnip. It tastes more like parsley, which is not really a surprise. Parsley roots don't get as sweet and delicious when you roast them as parsnips do, in my opinion - I get plenty of both from my Community Supported Agriculture box and buy a lot of parsnips as well.

If you can't find parsnips you could use parsley root as a substitute rather than going without. On the matter of "baby" parsnips --  I just cut the large ones into more pieces. The centre of the largest ones are woody sometimes, but unless it's 4" or more across (which I have seen) you have nothing to worry about.