Below are the places where gesneriads have been seen for sale. Saintpaulias (african violets) are commonly found in grocery stores and nurseries. If you find other gesneriad sources in the San Francisco Bay Area, please let us know and we'll add them to this list.
San Francisco Botanical Garden - Aeschynanthus, Streptocarpus
The Dry Garden Nursery (Berkeley) - Sinningia
East Bay Nursery (Berkeley) - Nematanthus, Aeschynanthus
Cactus Jungle (Berkeley) - Sinningia, Streptocarpella
UC Berkeley Botanical Garden - Aeschynanthus, Kohleria, Sinningia
Annie's Annuals (Richmond) - Aeschynanthus, Nematanthus, Sinningia
Ruth Bancroft Garden (Walnut Creek) - Sinningia
San Mateo County
Orchard Supply Hardware - Aeschynanthus (curly lipstick), Nematanthus, in hanging pots
Trader Joe's grocery stores - Sinningia (florist gloxinnia)
Half Moon Bay Nursery
The Gesneriad Society
The Gesneriad Society has a list of gesneriad suppliers on the website.