37- 
w&e burned off, exposing what appears to be ordinary talus 
material, composed of angular* unwashed fragments of sand¬ 
stone, mostly 1-3 dm. in diameter. 
"Burn" associations had started over the entire area, 
being further advanced at some points than at others. She 
commonest herbaceous pioneers consisted of Krigoron canadensis 
L. (horseweod), JBpiloblum angustlfollun L. fprroat willow-herb , 
Aster raacrophyllu s 1., .uraliu hispid a Vent, (bristly sarsa- 
\ 
parilla), and Holygonun Pour-la si 1 Greene. Amongst the shrubby 
species coming in next tho following were noted:- Hub us purvi - 
florus (s-lmon berryJ, hunbueus racemose L. (red-borried eldor), 
Piervillu henioera Mill* (bush honeysuckle), Rhus typhina L. 
(staghorn sumac), and Kuhns ldaous X,. vur* aouleutlsslmua ( C. 
a. Mey.) Hegel & Tiling. Tliese are followed by ? run as p pansy 1 - 
vanica I». f., (wild red cherry), ^ cor spicatun Lam. (mountain 
maple), seedling aspens and occasional seedlings of sugar 
rauplo ( iicer Bacoharum ). Hemlock seedlings undoubtedly come in 
at a later stage, finally displacing the maple. One of the 
most noticeable elements of this secondary succession is Rubus 
parviflorus . The plant spreads rapidly over large areas by 
stems just below the surface, these stems sometimes being 
several meters long. The foliage forme a "leaf mosaic n which 
reduces the light to such an extent thut shade-tolerant speci os 
are able to make on early start, thus probably hastening the 
