1) Matisse Patterns in The Rosaire Chapel - Ville de Vence.Opuntia inspired patterns are common in Matisse's work. This piece is stained glass in the Rosaire Chapel a chapel designed for Dominican nuns by Matisse. The image below is a screen shot from an interesting documentary about the Chapel and a nun who worked with and modeled for Matisse.
A screen shot from: A Model for Matisse
2) Giorgio Morandi's Cactus Painting.Italian still life painter whose cactus painting is an oddity among mostly vases bottles and bowels. The book sadly gives no genus nor species for this plant but perhaps a Parodia magnifica? Pachycereus pringlei? I would love to hear your suggestions.
Giorgio Morandi 1890-1964: Nothing Is More Abstract Than Reality
3) Georgia O'Keefe- Yellow Cactus