Hi.

I'm wondering if anyone in this group can help me to ID a plant.

I live in Ithaca, NY (in the Finger Lakes region), which has fairly
rainy, temperate climate. The plant in question looks like a kind of
false bamboo.

It grows to about 9 feet and has palmate, bamboo-like leaves spaced
alternately along a hollow, bamboo-like stalk. Dried stalks of dead
plants are reedy and brittle. The "root" is a solid clump of tuberous
tissue that usually looks black. It has a single tap root and shoots
off many rhizomes to propagate other plants at an alarming rate. In
fact, this plant is insanely prolific. It grows and reproduces very
fast. It seems to like sandy soil that is (probably) also high in
nitrogen. When it flowers in late Summer, it does so with small white
flowers arranged closely around a single stem.

I've noticed it mostly in areas that have been clear cut and plowed
(like new hillsides at construction sites and along roadways). I refer
to it as a "recovery plant."

Any help to get me in the ballpark of genus and species would be
greatly appreciated.

Thanks!
David