With regard to the production of water-permeable seeds by Bonamia menziesii and of water-impermeable seeds by Bonamia grandiflora, Jayasuriya et al. state on page 232 of the Discussion that they are not aware of another example of this occurrence between species in the same genus. However, A. Meisert (Seed Science Research 12, 121–128, 2002) found 100% permeable seeds versus 100% impermeable seeds between species of Erodium and between species of Pelargonium (Geraniaceae). As in seeds of the two Bonamia species, the water gap is open in water-permeable seeds of Erodium and of Pelargonium species and closed in water-impermeable seeds, and it is the only route of water entry into the permeable seeds; and also, of course, in the impermeable seeds after they become permeable (A. Meisert, D. Schulz and H. Lehmann. Plant Biology 1, 311–314, 1999). The water-impermeable palisade layer prevents entrance of water into the seed at other places on the seed coat in both water-permeable and water-impermeable seeds of Bonamia, Erodium and Pelargonium (Meisert et al., 1999; Jayasuriya et al., 2008).
K.M.G. Gehan Jayasuriya
Jerry M. Baskin
Carol C. Baskin