When we were young, my brave and crazy parents took us on road trips nearly every summer. All eight of us would pile into the suburban and head out to either an informal family reunion or some sort of nature themed trip. a trailer. We stayed as much as possible at KOAs over the course of the trip. And aside from hitting the KOA general store for CANDY!, my favorite activity was tree identification. I would pick up local tree guides in the various towns we would visit. Or my indulgent mother would even spring for a field guide in book form. We seemed to really enjoy New Mexico and Colorado more than anything else and my most treasured field guide was Rocky Mountain Wildflowers (from Peterson Field Guides). The trees were harder for me. I remember being in the woods around Breckenridge trying to determine whether what I was looking at was, in fact, an Engelmann spruce.
I still do this, only we involve the kids a lot more. Even at two, Baby Boy is able to identify some of the flowers by name in the backyard. Little Girl is further along and is now (suppressed squeal) asking about the Latin names to all her favorite flowers. A mandatory part of any vacation we take includes a stop by the local nature centers and nurseries. Recently we visited one on an otherwise errand related trip. I put together an album over there in my sidebar with photos and a few descriptions of the fun things we saw.