GIANT tubers found- what the heck?

I recently found a few gigantic turnip-like tubers near my home in San Diego, Otay Mesa A housing development brush crew evidently dug them up in preparation for grading. They vary is size from canteloupe-sive to medium TV set size. I brought home and planted a pumpkin-sized one. What have I done? My first guess is a nettle-like vine, but no evidence of the above ground plant is left. Please respond to my email, I can't check this board often.</p>

[WendyLyn]

I am new to the forum and know this is an old post, but wanted to respond. It sounds like the tubers are from the Marah plant, also known as Wild Cucumber or Manroot, so named because the tubers can get to be as big as a man's torso. These are one of my favorite viney shrubs and there are many species identified by the leaf. The leaves are palmate and the fruit is a spiny, green ball. They don't bloom every year, but when they do, they usually sprout from beneath a shrub and use the shrub for support. I have only seen them bloom a few times in the desert where I live. One year, it was so wet, that it seemed every juniper bush in the vicinity had a vine on it. (Leave it to those packrats to stock up on the seeds!)
Anyway, since it has been six years, I wonder if you ever got them to grow.
Wendy