Are these two weeds both lambsquarter?

Question

These two western Idaho weeds look like lambsquarter to me. One of them is blunt, and the other one is pointy (and much more susceptible to leaf miners and some disease that wilts the shoots and leaves). Are they both lambsquarter? What are the variety names, if you can tell? Because of the immaturity of the weed in the second picture, you might be tempted to say it's bind weed or something (but it's not; it's not a vine; the growth habit is just like that of the blunt variety).

Blunt variety (picture 1):

Blunt variety (picture 2):

Pointed variety:

Answer 1

The first two pictures ('blunt') appear to be lamb's quarters. As for the "pointy" one, an identifying characteristic is the red or purple-ish stem and underside of leaves when the plant is young.

More details from the Ontario (Canada) Agriculture Ministry guide to weeds:

Stems & Roots: 20-200cm (8in.-6½ft) high, branched or unbranched, smooth, green or with reddish or purplish lengthwise stripes and ridges

Leaves: First 2 or 4 true leaves apparently opposite (2 per node), but all later leaves and branches distinctly alternate (1 per node); leaves stalked, the blades 3-10cm (1-4in.) long, lance-shaped or more often broadly triangular with irregular, usually shallow teeth; leaves green or grayish due to a covering of a white mealiness or powderiness, sometimes with reddish undersurface on young plants.