Vegetative Key to Goldenrods of New England

Goldenrods (Solidago spp.) are abundant throughout the northeast, but there are so many that it is often very hard to tell them apart. Most dichotomous keys to this genus require reproductive (flowering/fruting) structures, but it would be useful for me to have a good way of telling them apart with only their vegetative features. I realize that such a key may not be as precise (given that most pre-molecular taxonomy is based on reproductive structures), but thought I'd give it a try.

I am in the process of compiling photographs and my notes into a visual key to this genus at least to species. For now, here is a list of the 26 goldenrod species found in New England (including the states where they are found) (thanks to Arthur Haines (2011) for this source):
I have included photos for several so far.

S. aestivalis (CT, MA, ME, NH, RI)
S. altissima (All states)
S. arguta (All states)
S. bicolor (All states)
S. caesia (All states)
S. canadensis (photos) (All states)
S. erecta (CT, MA, RI)
S. flexicaulis (All states)
S. gigantea (All states)
S. hispida (All states)
S. juncea (All states)
S. latissimifolia (CT, MA, RI)
S. leiocarpa (ME, NH, VT)
S. macrophylla (MA, ME, NH, VT)
S. nemoralis (All states)
S. odora (CT, MA, NH, RI, VT)
S. patula (CT, MA, NH, VT)
S. puberula (All states)
S. rugosa (photos) (All states)
   - Stem 30-150(-250) cm tall
   - Leaves mostly cauline, not triple nerved, not clasping, larger ones 3.5-13 x 1.3-5 cm

S. sempervirens (CT, MA, ME, NH, RI)
S. simplex (MA, ME, NH, VT)
S. speciosa (All states)
S. squarrosa (CT, MA, ME, NH, VT)
S. uliginosa (All states)
S. ulmifolia (CT, MA, ME, RI, VT)

References:
Gleason, Henry. A. and Cronquist, Arthur. Manual of vascular plants of northeastern United States and adjacent Canada. 2nd ed. Bronx, NY: The New York Botanical Garden, 1991