Baby parsnips vs. parsley root
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.