Et tu, Jack?

One of the plants I saw on my ride down the rail trail from Masontown to Morgantown last Saturday had me puzzled.  While it looked vaguely like a Jack-in-the-Pulpit (Arisaema triphyllu), I was certain that this was something different.

Compare it, for example, to this picture that I took a month earlier.

I sent this picture to the Herbarium Curator at WVU, and she informed me that this is also a Jack-in-the-Pulpit:

Arisaema triphyllum is highly variable, leading to the recognition of several subspecies (sometimes treated as species). The differences you see (size, color, shape, etc.) may be due to site/climate, plant age/sex, and ploidy level (chromosome number), as well as genetic factors.

Sneaky little buggers.