Here are some sources for pitahaya fruit and plants. White-fleshed varieties are usually called dragon fruit. At Vietnamese stores and nurseries, you might need to ask for thanh long.
* Bien Hoa Farm. Dragon fruit plants and fruits. Open weekends, 8 a.m. to 5 p.m. 275 Stewart Canyon Road, Fallbrook; (760) 728-8768.
* Dalat Farm. Dragon fruit plants and fruits, in limited supply. Open Monday through Friday, 8 a.m. to 6 p.m. 11130 E. Riverside Drive, Ontario (between Haven and Milliken avenues, under the power lines).
* Melissa's World Variety Produce. Dragon fruit by mail-order. (800) 588-0151.
* Mimosa Nursery (Anaheim). Dragon fruit plants in 7-gallon pots, $49. Open daily, 8 a.m. to 5 p.m. 2700 W. Crescent Ave, Anaheim. (714) 828-0780.
* Mimosa Nursery (East Los Angeles). Dragon fruit plants in 7-gallon pots, $30. Open daily, 8 a.m. to 4:30 p.m. 6270 Allston St., East Los Angeles. (323) 722-4543.
* Orchid Garden (Jim Weiss). Magenta-fleshed pitahaya fruits and plants. Season for fruits August and September. At Venice farmers market, Venice Boulevard at Venice Way, Fridays, 7 to 11 a.m.; and Torrance, 2200 Crenshaw Blvd., Saturdays 8 a.m. to 1 p.m. (Weiss will have a few fruits at this Friday's market, but the season is almost over).
* Papaya Tree Nursery. White-fleshed, red-fleshed and yellow pitahaya plants; in 2-gallon pots, $65; 5-gallon pots, $155; 10-gallon pots, $225. Fruits available occasionally. Call for appointment. 12411 El Oro Way, Granada Hills. (818) 363-3680.