Weed of the Week - Ground Ivy/Red Deadnettle

I can't resist this picture of real ivy (Hedera helix) and "ground ivy" (Glechoma hederacea L). The similarity stops with the creeping habit.  Everything else about them is different.  Here is my best shot at capturing the ground ivy emergent leaf:

While it is not at all like ivy proper it is quite similar to henbit and purple deadnettle, both of which are in the same (mint) family: Lamiaceae.  Now I was sure I had henbit in my garden...

.... but it turned out to be purple deadnettle.  This is a low spreading plant which is why I didn't at first  see any association with the 3ft high stinging nettle or even the white deadnettle which is considerably taller and more statuesque:

White Deadnettle

Out in the woods I have an eye on what I believe to be purple deadnettle behaving a lot more like I would expect:

Purple Deadnettle?

a. It isn't flowering yet and b.  it is standing tall and proud.

Either they are different plants or it is behaving quite differently in different circumstances. Watch this space for when the jury returns (or flowers appear on the wild specimen).  At any rate I have yet to locate henbit, even though I am now primed to spot it with similar flowers and characteristic whorled leaf.

I am really rather enjoying my excursion into wildflower/weed identification which I took up in earnest this winter as a bit of an off season filler, but the demands of spring sowing for the allotment and the school garden mean that I will not be investing much time in research for the time being.