I think the spines on the midrib under the leaves point to Lactuca serriola. (Lee Anne's plant)

Prickles 1–5 mm long along the midrib on the underside (dorsal) of a large leaf

http://www.naturemanitoba.ca/b...

Actually, the entire underside of the leaf is prickly...

All of it Lee Anne?

LEAVES basal and stem, alternate, simple, deeply lobed to toothed to entire, clasping at least below, sessile, 3.5–25 cm long by 1–20 cm wide, reduced above, often with axillary growth; lower stem leaves with a partial twist near the stem exposing the dorsal (lower) side of the blade and the midrib with one row of prickles 1–5 mm long (not hurtful) along most of its length, prickles absent on smaller leaves and near the blades’ apices, glabrous above, the margins irregular with short prickles; upper stem blades mostly entire and with fewer prickles; subtending leaves (bracts) of floral branches 0.4–20 cm long by 0.3–9.5 cm wide; auricles pointed, toothed.

Check out these under side leaf photo's for Lactuca serriola:

http://en.wikipedia.org/wiki/L...

http://www.illinoiswildflowers...

It's some type of wild lettuce, but it's not Lactuca serriola. I'd guess Tall Blue Lettuce (Lactuca biennis), but it's just a guess without a picture of the flowers and/or a better view of the undersides of the leaves

http://www.minnesotawildflower...

Lactuca biennis:

Spines on plant: the plant has no spines

http://gobotany.newenglandwild...

All leaves are hairy, especially the underside

http://www.minnesotawildflower...

Key ..

http://www.efloras.org/florata...

New pictures :)

underside of leaves fuzzy


Lower stems purple


top of plant

They look like spines rather than hairs, and look to be on the veins or ribs only.

There's another key for species in Saskatchewan, the trouble with keys is you have to follow through from the beginning and they don't necessarily mention all features. The key starts with pappus colour, you will need to wait for flowers then let them go to seed to use the key.

http://www.usask.ca/biology/ra...