Southern Park Mountain Distriet. 555 
Colorado is sometimes found in admixture mostly with Picea Engelmanni, but its most character- 
istie growth is found on those areas where it oecurs alone or greatly predominates over other 
species. It is uncommon in Pikes Peak Forest Reserve. In Plum Creek Reserve, it is nowhere 
abundant and in South Platte Reserve, its distribution is peculiar and irregular. It grows most 
abundantly on the higher plateaus and on northerly slopes at altitudes ranging between 8,000 
and 10,500 feet exceptionally reaching 11,000 feet, but never extending to the highest timberline. 
It is accompanied by a parasite Arceuthobium (Razuomofskya) americanum. 
5. The principal tree of the valleys in the Flathead Forest Reserve is the 
larch, Larix occidentalis; whether this formation is widely distributed has not 
been determined. The western larch is essentially a bench-land tree associated 
with Pseudotsuga, Pinus Murrayana, Abies grandis, Pinus monticola, Picea 
Engelmanni, Tluja plicata and occasionally Abies subalpina, Pinus ponderosa 
and western coast hemlock, 75uga Mertensiana, also certain deciduous trees, 
This type of forest gradually passes into that in which ZPinus monticola pre- 
dominates. As a tree the western larch does not tolerate shade and cannot 
reproduce itself unless an opening be made first in the forest. 
Acer glabrum gives decided tone to the undergrowth of this forest type which consists 
of Philadelphus Lewisii, Holodiscus ariaefolius, Menziesia glabella, Taxus brevifolia, Spiraea 
betulaefolia (= S. lncida), Elaeagnus argentea, Cornus stolonifera, Sorbus sambucifolia, Viburnum 
pauciflorum, hepherdia canadensis, Juniperus communis, J. sabina, J. scopulorum, Fatsia, Rubus 
Clintonia uniflora, Adenocaulon, Tiarella &c. — he characteristic non-tree species of the sub- 
alpine belt on Pikes Peak, according to T. D. A. COCKERELL, are Aquilegia brevistyla (= A. saxı- 
montana), Phacelia sericea, Castilleja pallida, Pyrola chlorantha, Polemonium humile var. pulchellum 
(= P. seopulinum), P. mellitum, Atragene oceidentalis, Erysimum asperum, Potentilla fruticosa, 
Rubus strigosus, Fragaria americana, Valeriana edulis, Carduus eriocephalu (= C. scopulorum), 
Achillea lanulosa, Helianthella Parryi, Senecio MacDougalii (= S. eremophilus), Pentstemon 
glaucus, Mertensia ciliata, Sedum rhodanthum, Zygadenus elegans, Thalietrum alpinum. 
ceptibly into dense forests of Piea Engelmanni associated with the spruce 
in the open edges of the dense forest are found Populus angustifolia, P. 
tremuloides and Betula papyrifera. In the dense woods the undergrowth is 
scanty, sometimes only one or two species are present. Ahamnus alnıfolia 
is the most common plant in pure spruce growths, although Cornus stolont- 
fera is often found. In the narrow strip of this forest along the streams 
nearer the mountains Fatsia (Echinopanax) horrida and Veratrum californicum 
are present‘). | R 
The Picea-Pseudotsuga Facies in Colorado consists of Picea Engelmannt, 
Pseudotsuga Douglasü, Picea Parryana (= P. pungens). _Pseudotsuga 
1) WHITFORD, Harry N.: The Forests of Flathead Valley, Montana. Botanical Gazette 
XXXIX; 194—218. March 1905. 
