1991 Volume 69 Pages 49-63
This paper presents the results of SEM investigations of wall markings on the inner face of the hyaline cells of the branch leaves of eight species of Sphagnum, S. papillosum Lindb., S. palustre L., S. henryense Warnst., S. affine Ren. & Card., S. portoricense Hampe, S. squarrosum Crome, S. teres (Schimp.) Ångstr. in Hartm., and S. wulfianum Girg. Two types of markings are described and illustrated: papillae and ridges. The papillae are simple or compound and are sometimes coalesced into straight, curvilinear, or wavy rods or lines. The ridges are parallel or curved into networks. Papillae on the inner walls of the hyaline cells of S. palustre are described for the first time. Papillae and ridges occur on some of the fibrils of the hyaline cells, indicating that in development the extra ornamentations are deposited after the fibrils have formed. The SEM reveals faint wall markings that are not visible with the light microscope.