What I think is really cool, and that I didn't quite realize from textbook descriptions back when I was in school, is that when seeds germinate the first leaves that pop up actually aren't the true leaves of the plant. (they are called cotyledons or seed leaves). The true leaves, the ones that you would recognize and allow you to identify the plant are the next to develop, but the cotyledons are what nourish and feed the plant as it is germinating - basically they are an energy boost to get the new plant up to the surface so it can start photosynthesizing...
Marigolds with their first "True Leaves"
So every day as I've been watching my plants I've been counting true leaves, analyzing seed leaves and waiting for the true leaves that look like the plants I'm growing to develop. Maybe long time gardeners are all aware of this, and it is something I missed out on, but I had totally forgotten all about it, and as I've been gardening all this information has jumped back to the front of my mind...
What I am curious about (caution: I am about to get really "sciency") is how come ALL the plants I am growing are dicots (have two seed leaves when they germinate). Are there any regular garden plants/flowers that are monocots (have only one seed leaf when they germinate). Did I just select all dicots at random, or are monocots simply more rare. So, these are some of the things I think about, although I am not sure most gardeners even care. I am a bit of a geek that way and "school-type knowledge" tends to stick in my brain, while I cannot seem to remember what groceries I need to buy when I get into the grocery store.