Pilocereus versus Cephalocereus (Cactaceae)

Abstract

D. R. Hunt has shown that Cephalophorus Lem. (Cact. Hort. Monv. xii, 1838) was a provisional name, but his assertion of the validity of Pfeiffer (Allgemeine Gartenzeitung 6: 142, 5 May 1838) cannot be sustained (Taxon 17: 543-544, 1968). It, too, was a provisional name invalid under Article 34 (3) of the Code, being mentioned incidentally without intention to introduce it. The evidence is as follows. Pfeiffer was reviewing Lemaire's book in which had tentatively suggested a new genus Cephalophorus, for the Old Man Cactus, then known as Cereus senilis (Haw.) DC, and had made the appropriate new combinations. This was, however, only intended If the experts are unanimous that a new genus may be formed for this plant (ex Hunt, l.c.). While Pfeiffer certainly agreed about the need for a new genus, the last relevant words of his review are Durfte . . . vorzuziehen sein, i.e., would have to be preferred, not must, as in Hunt's translation. was thus a conditional, not a categoric suggestion. Pfeiffer mentioned the name once only, it is in only slightly larger type than the rest of the review, it was not used by him in combination, it is not in the annual index of the newspaper, and most significantly, Pfeiffer never advanced it again. Clearly, he felt that he had no right to do so. Lemaire, not he, was the one who had examined and described the inflorescence that singled out the Old Man Cactus from other Cereus species, and had suggested, albeit tentatively, generic and specific names for it. accepted Pfeiffer's support for the creation of a new genus as sufficient: Pfeiffer was the leading cactus authority of the day (W. T. Steam, The Cactus Journal 8: 45, 1939). was not obliged to use any previously mentioned name and chose the excellent Pilocereus, making the appropriate new combination for the Old Man Cactus (Cact. Gen. Nov. Sp. 7, 1839). This name was universally used for the next fifty years, many new hairy Cereus species without a pronounced cephalium-like inflorescence being added during that period. Cactus enthusiasts were, however, aware of the existence of as a synonym. C. F. Forster in his Handbuch der Cacteenkunde, 351, 1846, and Prince Salm-Dyck in Cactae in Horto Dyckensi Cultae, 39, 1850, gave it as such under Pilocereus. Responsibility for the modem use of rests with Karl Schumann. In Martius Flora Brasiliensis 4 (2) Fasc. 108, 1890, he simply asserted that it had priority and that Pilocereus sine dubio Pfeifferiano postponendum est. This was obviously unacceptable to the by then numerous German cactus enthusiasts, with whom Schumann was in close touch as President of the newly formed German Cactus Society. Whether the amateurs influenced him or not, as they did on his own showing when he abandoned his Zygocactus (1890) only two years later, he nevertheless partially recanted in 1894, restoring recognition to Pilocereus Lem. for many species. He retained Cephalocereus Pfeiff. (em.K.Sch.) for four species only including the Old Man Cactus (Die natuirlichen Pflanzenfamilien 3 Abt 6 & 6a Lief. 103, 181, 1894). He conceded that some uncertainty existed on the generic names. Both genera, he said, had formerly been held as Pilocereus, but was undoubtedly older. He then remarked implausibly that Lemaire had created Cephalophorus which was perhaps published earlier still, a fact which I cannot establish today. It was a fact self-evident from Pfeiffer's review. Schumann retracted his inconvenient complete dismissal of Pilocereus, writing that now that he had convinced himself of the need for separating most of the later species from the original two, both names can enjoy their rights. The rights he claimed for Pfeiffer's name were not even claimed by its author! In his monograph of 1897 (Gesamtbeschreibung der