try Dolphin Pet Village. Corner of San Thomas Aquino and Campbell next to a Hobby Shop.
They have riccia (crystalwort) in little tubs or plastic baggies but it's $20 bucks! The glosso is great - I believe it's $3.50 for a pot, but it's a very, VERY full pot.
They also carry other not so common plants. Be prepared to pay a little bit more, but then again, they have awesome sale prices on different plants each week. Their supplier is Florida Plants, I believe, and all the plants are labeled so you're sure you're getting true aquatics.
Another place to try: Petco in Sunnyvale. Plants come in usually Wednesday afternoon, but I'd go right before they close cuz the girl that works there gets kind of snippy if it's really busy. Tons of great potted plants and all for the same price so you'd get anubias nana, amazons, and dwarf hairgrass for about 4 bucks each. Their supplier is Horizon growers in Ramona, who, unfortunately, never labels their plants. If you know what you're looking for, it's all good. Or if it's not too busy, talk to one of the fish people.
The other places I've been to around the South Bay either don't carry anything other than some overpriced anubias or try to sucker you if you seem like a newbie.
Oh yeah, almost forgot - PetClub, next to Costco, on Rengstorff right off of 101. Go Saturday mornings when the guy with the glasses is there. He doesn't know much about plants, and they only carry potted,but it's a good place to start if you want cheap (but good) stuff.
Hope that helps!