280 BOTANICAL GAZETTE [APRIL 
sunlight reaching the ground in quantity insufficient for a varied 
herbaceous ground flora. This in effect brings the meadow into 
the forest, or rather the forest into the meadow, since the last 
is antecedent to the climax vegetation of the district, the conif- 
erous forest. -There is then difficulty in describing these associa- 
tions apart, though they are distinct enough below. 
The one tree of this forest which usually forms dense stands is 
the red fir (Abies magnifica). It favors low benches and bottoms 
of valleys and is not often found upon the slopes save as a fringing 
forest along water courses. It does form a considerable element 
in the forest on the great moraines, however, the loosely aggregated 
_ soil of which permits deep root penetration. On the great moraine 
east of Fallen Leaf Lake the red fir is the principal tree. This dark © 
fir forest has few shrubs, but does support a characteristic flora of 
ericaceous perennials, such as Pyrola pallida, P. picta, Chimaphila 
Menziesii, C. umbellata, and Sarcodes sanguinea. The fir forest 
is an exclusive association, few of the other Canadian species en- 
tering into it, doubtless excluded by the insufficient light for seed- 
ings. 
The Canadian pine forest has a very different aspect, being open 
or even parklike in the spacing of the trees. Neither of the two 
pines which compose it (Pinus Murrayana and Pinus monticola) 
attain large size, but are widely branching, especially at their uppet 
levels. Pinus monticola continues into the Hudsonian and at 
times becomes a tree line form, but Pinus Murrayana is relatively 
constant about Lake Tahoe as a Canadian exemplar. The lodge 
pole pine is a vigorous seeder, and all about the meadows in the 
Canadian, where drainage has permitted, the young seedlings 
form a dense border. By subsequent drying out of the weaker 
individuals the open character of the mature forest is attained. 
Pinus Murrayana is often attacked by Arceuthobium americanum. 
Within this open forest grow several shrubs: Salix Scouleriana 
along the damp ravines, and with it Vaccinium occidentale, Ribes 
cereum, R. nevadense, Purshia tridentata (this forming rounde 
clumps which in the Hudsonian become dense polsters), and above 
all as a typical undershrub, Ceanothus cordulatus. The herba- 
ceous flora embraces Melica aristata, Spraguea umbellaia, Stellarta 
Jamesiana, Lupinus calcaratus, L. apertus, Viola N uttallii, Ortho- 
