1 



204 



Populus along streams. These are yellow to orange at 

 this seas on • 



Popiilus tremuloides comes in at about the altitude 

 of Idaho Springs and soon become very abundant* The 

 coniferous forest changes to almost pure spruce, the 

 two kinds mixed. Large patches especially on slopes 

 are covered by a pure stand of aspen, or mixed aspen 

 and conifers. The distribution of aspen is patchy and 

 shows no order, apparently is result of fire. There 

 are also patches of very even aged small pine that 

 must have resulted from fire. The aspens show a very 

 uneven sequence of color change and loss of leaves. 

 T^ose in patches on slopes have mostly lost their 

 leaves, though an occasional small patch among conifers 

 is a brilliant yellow, as are usually those along 

 ravine-bottoms. Here and there is one that is a 

 beautiful flame-pink or orange. Occasionally one is 

 still partly green. The trunks are mostly a pale olive 

 drab, but there are occasional areas where they are 

 almost white. 



Below 8000' the forests are largely on north-facing 

 slopes. South ones are covered by sparse brush and 

 Juniper. The conifer forests from 8 to 11 or 12000' are 

 mostly spruce, with occasional fir and pine. The growth 

 form is slender spire-like. The forests are dense and 

 rather tall, the trees not very large in diameter. The 

 two species of spruce are not very clearly marked here, 

 but there are green and bluish individuals and ones 

 with pinkish or brownish scaly bark and ones with smooth 

 fir-like white bark. Ripe cones are abundant both on 

 trees and on ground. 



There are little undergrowth and little ground cover 

 in this forest. Patches, occasionally of a low Vaccinium 

 (or Salix?) that are turning yellow or red. 



At timber-line, Pinus flexilis becomes abundant and 

 in places forms a krumholz. The timber line is uneven 

 but rather abrupt. 



All through the upper forests and especially near 



205 



tiiriber-line tiire spraces with dead tops. 



Above timber-line the grass is straw-color and varies 

 greatly in density. There is a rich flora of herbs 

 mixed with it. There is a thin (10-15 cm.) layer of 

 mor or raw humus that is rather black. 



Upward the grass and other herbs get shorter till 

 near the summit of Mt, Evans there is a very low turf, 

 1-6 cm. tall, still quite a mixture of species. At 

 the summit this almost disappears, showing only on 

 flattish spots between boulders, in crevices and in 

 sheltered places. Su/wvwv^ i^, l-fioft- 



The virtual disappearance of vascular plants above 

 14000 ft. is probably due to the fact that the substratuir 

 changes almost entirely to great joint blocks and 

 exposures of a coarse pink granite, with soil only in 

 the pockets where the vascular plants occur. 



On the rocks themselves is a small flora of crustose 

 lichens, - black, green, bright yellow-green, yellow, 

 and rarely orange -. The lichens are on all exposures 

 but more abundant on the under sides of overhanging 

 slabs and projections. Near the summit a pica was 

 seen, also a weasel. Other picas were heard. On the 

 slopes was a small flock of medium sized white or 

 partly white birds. Several bright blue small birds 

 were seen* What/ appeared to be a Nuttall jay was Iseen 

 at timberline in the pines. 



