pilosocereus

The taxonomic history of the genus name Pilosocereus is somewhat complicated. In 1838, Charles Antoine Lemaire created a section within the genus Cereus, C. sect. Cephalophori, based on Cereus senilis and C. columna-trajani. In the same year, Ludwig Pfeiffer published the genus name Cephalocereus, also based on Cereus senilis. In 1839, Lemaire raised his Cereus sect. Cephalophori to a genus under the name Pilocereus, presumably unaware of Pfeiffer's earlier name. Since both Cephalocereus and Pilocereus are based on the same type (i.e. Cereus senilis), the later of the two names is superfluous, and so must be rejected under the International Code of Nomenclature for algae, fungi, and plants (ICNafp). In 1894, Karl Moritz Schumann decided that Lemaire's Cereus sect. Cephalophori needed to be split into two genera, rather than treated as one genus. He retained Pfeiffer's Cephalocereus, and attempted to use Pilocereus for the other.{{Citation |mode=cs1 |last1=Schumann |first1=Karl Moritz |date=1894 |editor1-last=Engler |editor1-first=A. |editor2-last=Prantl |editor2-first=K. |contribution=2. Pilocereus Lem. |title=Die Natürlichen Pflanzenfamilien |pages=179–182 |publication-place=Leipzig |publisher=Wilhelm Engelmann |contribution-url=https://www.biodiversitylibrary.org/page/16816036 |access-date=2025-06-26 |volume=3 (part 6a) |name-list-style=amp }} Schumann removed from Pilocereus both of the species originally designated by Lemaire; however, this is not allowed by the ICNafp which requires that a name is permanently attached to its type, so Pilocereus sensu Schumann is equally illegitimate.

Subsequently, the genus name Pilocereus was widely used and several attempts were made to legitimize it. One possible solution would have been to conserve Schumann's name against Lemaire's. However, a proposal to do so was not accepted by the 1954 International Botanical Congress.{{Cite journal |last1=Byles |first1=R.S. |last2=Rowley |first2=G.D. |date=1955 |title=What is to become of the Pilocereus? |journal=The Cactus and Succulent Journal of Great Britain |volume=17 |issue=2 |page=32 |jstor=45134083 |name-list-style=amp }} In 1957, Ronald Stewart Byles and Gordon Rowley provided a solution by publishing Pilosocereus with the type species Pilocereus leucocephalus (which thus became Pilosocereus leucocephalus). They also provided names in Pilosocereus for all the species then placed in Pilocereus.{{Cite journal |last1=Byles |first1=R.S. |last2=Rowley |first2=G.D. |date=1957 |title=Pilosocereus Byl. & Rowl. nom. gen. nov. (Cactaceae) |journal=The Cactus and Succulent Journal of Great Britain |volume=19 |issue=3 |pages=66–67, 69 |jstor=45475966 |name-list-style=amp }}

{{As of|2025|June}}, Plants of the World Online accepted the following species:{{Cite POWO|title=Pilosocereus Byles & G.D.Rowley|id=299077-2|access-date=2025-06-26|mode=cs1}}

{{Reflist}}

• {{Commons category-inline|Pilosocereus|Pilosocereus}}
• {{Wikispecies-inline|Pilosocereus|Pilosocereus}}

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Category:Cacti of North America

Category:Cacti of South America

Category:Cereeae genera

Category:Flora of the Neotropical realm