This is far from being an Oxford debut show for John Thomson. In 2005 he was Artist in Residence at the Botanic Garden and exhibited at the University Museum of Natural History last year under the title disney meets DNA. His present show Say it with Flowers, at Christ Church Picture Gallery till July 8, extends more widely to comprise sculptures, works on paper, digital prints and sketchbooks. These items, executed in an extreme variety of media, are scattered in the galleries among the works of the old masters who mostly managed just with oil and canvas.

What has Thomson to tell us? His vision, whether in notebook form or fully realised, is disturbing and his view of nature' is unsettling. The sculptures are all in steel, plywood and fabric - a metal column, a plinth covered in fabric, and a mysterious subject. Poison Ivy is a Medusa helmet swarming with worm-like shapes; Rose Lane - mounted on pink flowery cloth - encompasses four items, one possibly tree-like, one just possibly rose-like, one inexplicable, one only just possibly related to an episode related elsewhere - "an ant crawled out of wallet at Pangbourne". Could these derive from the experience of the Botanic Garden?

An extensive display of digital prints helps one to follow the motifs of the sculptures; some of the tiny drawings are witty, like a Pisa tower of wobbly packages, or the Porgy and Bess flowers.

Works on paper, in ink and watercolour, are large, outdoor and airy, of wide landscapes scarred by tracks and motorways with, centrally placed, an ominous feature, usually man-made - Substation, or Changing Signals. Thomson doesn't like technological man, or the blood and butchery of his traditional trades. But his own natural world of sexy plums and worrying fruits, isn't very comfortable either.