My trees and shrubs field guide came Friday afternoon. I spent most of Saturday bouncing from one guess to another for what turned out to be a honey locust (not one of the guesses). It was a "thornless" variety. My guide had only those with thorns, the absence of which led me repeatedly down the wrong path on the dichotomous key.
But a bit of new knowledge changes the way the world looks just slightly. Whorls are different from alternating or opposite leaf groupings and compound leaves are different from tightly grouped single leaves. There are limited and memorizable distinct needle shapes. Some plants are distinguished by the pattern of scarring on their stems and others by the orientation of the veins on their leaves. I couldn't tell a birch from an elm at this point, but knowing the locations of such extraordinary variation illuminates the differences.
A block in the city is more vibrant when I have words to describe its shape and color. It turns out that I can ignore rather effectively the things for which I have no words. Sort of makes me wonder what else I'm missing out there.