Clave con fichas perforadas de las familias de los árboles mexicanos

Abstract

A preliminary card key to the families of Mexican trees is described, and two tables for the construction of this key are included. One table lists 97 characters, vegetative as well as reproductive, selected for the key. The other table presents the list of 119 families based upon Stanley´s Flora, and for each the numbers of the characters presented in the first table. Using hand sorted punched cards with holes or perforations on the margins, readers can construct their own key. The holes are numbered, the name of a family written on the center of a card, and notches are cut through all the cards in the hole numbered for a particular character. All the cards of families possessing this character fall out when the cards are shaken. Sorting continues for the other characters with the cards that fall out until only one or a few cards are left. Then the identification is verified with descriptions. Corrections and suggestions are desired