So, I was slightly wrong in my previous post about this mystery plant. My Nana pointed out that Granny actually referred to this as a teardrop plant (and not a tear plant), and upon googling teardrop plant I quickly found the information I was looking for.
In my online research, I’ve also seen it called the mother of millions (or thousands), Mexican hat plant, and chandelier plant. The forums at gardenweb.com were especially helpful in pinpointing the exact plant that I have. They directed me to bryophyllum.com (which has some very informative pictures!), where I learned that my plant is called bryophyllum crenatodaigremontianum. It’s a cross between b.crenatum and b.daigremontianum. I’ve discovered that the mother of millions (the name I prefer, naturally) is a particularly invasive succulent that’s been known to grow on almost any available surface (including bare bricks and pine straw). Many people consider this plant a weed, and it should be kept out of reach of pets as it’s leaves and especially its flowers are toxic when eaten. Apparently, this plant won’t think twice about choking out another plant it happens to share soil with. Because of this, it’s wise to keep these away from other plants altogether. The rosettes on the leaves are indeed the baby plants, and they can fall into neighboring pots and take them over if you aren’t careful. Therefore, total isolation is recommended for the mother of millions. A windowsill by itself or a big pot on the porch both seem like good places to me. I have yet to see them, but according to both Granny and the internet, the mother of millions produces pretty lavender flowers.