94 A Study of the Vegetation of 
viduals of Pseudotsuga and Abies, confined generally to the 
canyons and rich levels at the bases of north slopes. 
These mountain slopes were overrun by fire on August 21 and 
22, 1910. As they seemed to represent fairly the average forest 
conditions for northern Idaho, it was decided that here would be 
a most satisfactory place to carry on a study of the problem of 
natural reforestation. 
Among the first pioneers to reclaim the unshaded and charred 
soil were Funaria hygrometrica and Marchantia polymorpha. 
Cirsium palousense, Erigeron acris, and Epilobium angustifolium 
were the chief herbs, whose wind-blown fruits afforded them an 
early entrance. Likewise, the numerous seedlings of Salix. 
scouleriana may be accounted for in the same manner, while 
numerous others sprang up from the underground parts of the 
older willows characteristic of more open areas. The presence of 
Opulaster pauciflorus, Arnica cordifolia, and Erythronium grandi- 
florum may likewise be accounted for by the fact that the fire 
left unharmed the rootstocks of the shrub and of Arnica and the 
corms of the lily. 
In the spring of 1911 and the second year after the fire, Epi- 
lobium angustifolium was predominant everywhere. The indi- 
viduals varied from mere seedlings to plants 12-18 inches in 
height, often as many as 30 to 50 individuals occurring in a single 
square meter. Thousands of the smallest were succumbing to an 
epidemic of Aecidium. Next in importance to the fireweed was 
the thistle, Circium palousense, which with Antennaria luzuloides 
and the species enumerated as occurring the preceding year, 
formed a considerable herbaceous carpet over the burned area. 
Every inch of the ground otherwise unoccupied seemed covered’ 
with Funaria hygrometrica. The following shrubs, Opulaster 
pauciflorus, Rosa gymnocarpa, and Rubus parviflorus, which were 
more or less abundant, had, like several of the herbs in the fol- 
lowing list, been able to survive the fire by means of underground 
propagative parts. The bulbs of Zygadenus venenosus and Fritil- 
laria lanceolata, and the corms of Erythronium grandiflorum, all 
of which were present in considerable abundance, were found at 
depths of 5-7 inches below the surface of the soil. Other plants 
94 
