Identification of Grass and Morningglory Species with Simple Dichotomous Keys

Abstract

Agriprofessionals and technical college students took an examination without and with simple dichotomous keys. Without keys, only 15% and 30% of the agriprofessionals identified 71% or more of the grass and morningglory species (Ipomoeaspp. # IPOZZ), respectively; 97% scored in this range for both weed groups with keys. Without keys, no student scored higher than 40% or 30% on grass and morningglory species, respectively. With keys, all students identified more than 60% and 50% of the grasses and morningglories, respectively. For grasses, only 3% of the agriprofessionals and none of the students achieved an excellent (>90%) score without keys, while 56% and 8% did with keys. Twelve percent and 65% of the agriprofessionals achieved an excellent score on the morningglory species without and with keys, respectively; 42% of the students scored higher than 80% with keys.