Scanning electron microscopy of the seed coat in the genus Paulovunia (Scrophulariaceae)

A comparative study of the microscopic structures of external features of mature seeds of eight Paulownia species is presented. The external surface of the seed is made up of reticulate, apparently translucent cells, which laterally extend into wing-like structures. The laterally symmetrical wings are unequally extended in the micropylar and chalazal regions. The seed-coat ornamentation has a dorsiventral nature. Some special features of seed-coat morphology amongst the eight Paulownia species are discussed.