Summary The transmission, reflection and absorption spectra of a range of legumes including Pisum sativum L. were compared. The optical properties of the pea pod appeared to be within the middle of the range of species studied. The optical properties of the pod walls of five different varieties of Pisum sativum were investigated at three stages of development. The highest transmission of Photosynthetically Active Radiation (PAR) was shown by a yellow pod (JI 73), followed by a parchmentless variety (JI 468). A purple variety (JI 60) showed a very low overall PAR transmission, while a thicker pod JI 149 transmitted less light than the conventional JI 141 pod, but more than the purple. Overall transmission tends to decrease as the pods become more fully developed, while reflection increases slightly in the older stages. The apparent Red/Far-red ratio of light entering the pod was calculated for each variety at each stage of development. Varieties which lack chlorophyll in the mesocarp or lack a sclerenchyma layer, and therefore transmit more light, have a higher ratio than conventional pods in which the seeds develop in a more shaded environment. The significance of these changes in relation to seed development is discussed, as well as the implications of slightly increased near-UV penetration through the wall of the parchmentless variety.