THERE'S THE TINIEST defensive note in Rachel Osajima's introductory curatorial statement – probably in anticipation of the inevitable antediluvian protest of the museum's decision to showcase works by 20 local artists who are influenced by, but not explicitly identified with, craft or folk art. But Osajima shouldn't have to apologize, and neither should the artists; that so many of them are already known from the local gallery scene suggests that their mongrel mix of high art and craft is already recognized as a viable hybrid, and that worrying about these categories is really a bit old-fashioned. Names you may recognize include Amy Berk, Charles Linder, Jason Mecier, Rigo 03, and Becky Schaefer (if you missed Schaefer's fabulous Lara Croft needlepoints earlier this year, you've got another chance). Unlike conventional paintings and sculptures, many of the works derive their power from unique materials. Midori Harima, a Japanese artist who recently relocated to San Francisco, makes sculptures out of ordinary Xerox copy paper. Her forms recall Japanese Washi paper art, but their material ties them profoundly to contemporary office life – a global culture that transcends all national and ethnic boundaries. Philip Ross and Susan Johnson White can probably claim the most idiosyncratic substances of all. Ross cultures and manipulates shelf fungus (Ganoderma lucidum) into myriad forms, creating works that reference everything from drug culture to haute cuisine, bonsai trees, and rural American kitsch craft. White crochets doilies out of gut and hair, recalling the old saying about sows' ears and silk purses. Her use of bodily elements to comment metaphorically on matters of gender and domesticity allies her with many other contemporary artists both inside and outside the official craft and high art realms. Sat., 10 a.m.-5 p.m.; Tues.-Fri., Sun., 11 a.m.-5 p.m. (first Wed., 11 a.m.-7 p.m.), Fort Mason Center, Bldg. A, Marina at Laguna, S.F. $4, $3 seniors, free for members and 18 and under (free first Wed. and Sat., 10 a.m.-noon). (415) 775-0991. (Lindsey Westbrook)