What ingredients (available in specific regions) can I substitute for parsley?

You might try Thai or European celery leaves as a substitute.

Can you find seeds anywhere? Parsley is easy to grow in pots, so you could manage even if you live in an apartment.

1. Depending on what your original recipe is and what your tastebuds like, you could use any mild green herb although the character of the dish would be different: basil and dill do not taste like parsley.

2. Parsley is not 'just a garnish'! Many dishes, like tabbouli, absolutely rely on parsley. Parsley has its own flavor and texture (as you guessed when you said, "there must be something about the taste otherwise it would call for parsley within the sauce as well").

3. If your recipe calls for fresh parsley, you will want to use fresh parsley, or fresh something else in its place. Dried herbs cannot give the same vivacity.

I found this answer on the Discuss Cooking forum. If looking to substitute parsley for flavor do not use cilantro as "the flavors are nothing at all alike". Instead you can use

chopped chervil (closest to parsley that you can get, i think), angelica, dill, lovage, savory, basil, etc

You mentioned that you are making a pasta dish with sauce. So, what cuisine is the dish that you are cooking? I'd say replace the parsley with an herb or spice that fits the cuisine.

If for example, it was an Italian dish, I would have no hesitation in using basil. It's a different flavor, but fits the cuisine. Or a SE Asian dish, then cilantro might just work.

Second thing, try out other possibilities in the same plant family. Here's a link. http://www.clovegarden.com/ingred/py_parsley.html

Here's a possibility from the above link:

Mitsuba - [Japanese wild parsley, Cryptotaenia japonica alt. Cryptotaenia canadensis subsp. japonica]

Native to North America and East Asia this plant is used as an herb seasoning and sprouts are used in salads. It is described as similar to angelica.

Parsley is usually used more for looks than for taste. If you don't have it, then you can probably leave it out.

Cilantro leaves might do, depending on what flavor you're after. If it calls for fresh and you only have dried, don't bother though.

Some, but YMMV (meaning: I can't speak on availability, but I expect cilantro to not be a problem):

• Chervil
• Cilantro
• Earth Chestnut

I personally think parsley and cilantro are miles apart, but different strokes for different folks.