[en] Although holotype material of Calamophyton primaevum Krausel and Weyland has not been available since the Second World War, two fertile specimens of that species are in the personal collection of Professor H. Weyland. The purpose of this paper is to disclose the complexity of the organization of the fertile appendage. Formerly it was believed to consist of one segment that had dichotomized once and that had borne two pendulous sporangia, one at each branch. Numerous degagements of sporangia have revealed a complex morphology, consisting of one main segment divided into two secondary segments. Each supports three recurved side stalks which in turn bear
2 sporangia, a total of 12 sporangia. Each secondary segment terminates in two elongated projections. The morphology of the fertile organs is compared with that of two other species, C.bicephalum Leclercq and Andrews and C. forbesii Schopf. Great similarity of organization exists between C. primaevum and C. bicephalum. The possible synonymy of these two species is discussed.
