What would April be without a Prank?
The Museum of Hoaxes has a page dedicated to April Fool's Day Botany.
The page, dubbed "Plant life that exists only on April 1st," has 22 "species," i.e. pranks, that date from 1900 through 2019 and are some of the best April Fool's Day jokes ever played, botany aside.
Echinocereus dahliaeflorus -
According to the Museum, "A German garden journal, Möllers Deutsche Gärtner Zeitung (15:148), printed details of a fictitious species of cactus, Echinocereus dahliaeflorus, in its April 1900 edition. The editor of the journal apparently forgot his own joke because he indexed the cactus name at the end of the year." And in the 1922 book, The Cactaceae: Descriptions and Illustrations of Plants of the ..., Volume 3, by Nathaniel Lord Britton, and Joseph Nelson Rose, it stated of the Echinocereus dahliaeflorus that "The name is to be ignored." In 2018 Cara Giaimo wrote on atlasobscura.com that the original text of the joke translated Echinocereus dahliaeflorus, "is a cactus covered in sharp flowers" and "found in Madagascar, and its strange blooms perfectly solved a longstanding argument between members of the German Cactus Society and the German Dahlia Society."
Echinocereus dahliaeflorus, although the name is to be ignored, it is not to be confused with Cactus Dahlias which are not a joke and are "named for their spiky, cactus-like blooms - but are soft to the touch! Their pointed petals are rolled into tight tubes, making for an eye-catching star-shaped bloom."
Mix a little foolishness with your prudence: It’s good to be silly at the right moment. - Horace