The cell wall of Lilium pollen tubes contains less skeletal cellulose (Herth et al. 1974) than the pollen tube wall of Petunia (Sassen 1964, Engels 1974) and Nicotiana (Kroh & Knuiman 1982). A crystalline modification of polymeric /?-1,3-glucan predominates in the lily pollen tube wall (Herth et al. 1974). Since microfibril synthesis presumably is a membrane-bound process (Brown 1985), we studied plasma membranes of lily pollen tubes with the freeze-fracture procedure for comparison with plasma membranes of tobacco pollen tubes (Kroh& Knuiman 1985).