The conjugation of similar gametes, arising from distinct plurilocular sporangia, was observed by Berthold in Ectocarpus siliculosus and Scytosiphon lomentarius in 1880; and these observations have been recently confirmed in the case of the former species by Sauvageau, and in the case of the latter by Kuckuck.
From each locule of a plurilocular sporangium there is set free an oosphere, which, being furnished with a pair of cilia, swarms for a time.
It would thus seem that the explanation of the existence of two kinds of sporangia, unilocular and plurilocular, among Phaeosporeae, lies in the fact that unilocular sporangia are for asexual reproduction, and that plurilocular sporangia are gametangia - potential or actual.
The discovery by Brebner of the specific identity of Haplospora globosa and Scaphospora speciosa marks an important step in the advance of our knowledge of the group. Three kinds of reproductive organs are known: first, sporangia, which each give rise to a single tetra-, or multi-nucleate non-motile, probably asexual spore; second, plurilocular sporangia, which are probably antheridia, generating antherozoids; and third, sporangia, which are probably oogonia, giving rise to single uninucleate non-motile oospheres.