1915] SMILEY—LAKE TAHOE REGION 285 
on this rocky surface that one finds many of the growth forms 
associated with extreme life conditions: polsters, mat plants, es- 
paliers. It is this region of the high mountains that offers the 
closest analogies to the forms of desert plants, and it is here that 
some of the peculiarly desert genera (such as Eriogonum and Arte- 
misia among flowering plants, Cheilanthes for desert ferns) have 
made their deepest mark upon the alpine flora. Conditions on 
the broken talus are quite different from those of ledges, and a 
different group of plants grows on it: a high altitude dwarf chapar- 
ral formed of Ribes montigenum, R. viscossissimum Hallii, Grossu- 
laria lasiantha, Purshia tridentata, Aplopappus macronema, and 
Artemisia arbuscula. These may all grow intricately together, 
or separately, when all assume the same growth form, hemi- 
spherical polsters. On the more solid rock the mat form is the more 
common (Spraguea umbellatata, Phlox Douglasii diffusa, Chaenactis 
nevadensis). In crevices will be found Eriogonum marifolium, E. 
Wrightii, Gilia congesta palmifrons, Polemonium pulcherrimum, 
Eriophyllum integrifolium, and Senecio canus. Over the glaciated 
granite surfaces exposed in Desolation Valley Quercus vaccinifolia 
forms dense espaliers. On the granite also was found the only 
specimen seen of the arctic-alpine shrubby cinquefoil, Potentilla 
fruticosa. On wet granite ledges grow Scirpus criniger, Sedum 
integrifolium, Parnassia californica, and Erigeron Coulteri. Where 
a soil cover has accumulated on moist ridges are to be found Cas- 
siope Mertensiana, Lappula Cusickii, and Pentstemon procerus geni- 
culatus. 
As in the Canadian, so in the Hudsonian pine forest the mea- 
dow spreads under the trees and among the grasses (Agrostis 
Rossae, Festuca scabrella, Melica stricta) will be growing Brodiaea 
gracilis, Calochortus Leichtlinii, Gayophytum caesium, and A plo- 
pappus apargioides. A characteristic feature of high mountain 
meadows is the large percentage of carices and junci present; in 
the Hudsonian meadows of Lake Tahoe have been identified Carex 
capitata, C. Helleri, C. luzulaefolia, Scirpus pauciflorus, Juncus 
arryt, J. nevadensis, and J. subtriflorus. Common herbs of these 
wet meadows are Stellaria longipes, Saxifraga bryophora, Trifolium 
monanthum, Gentiana Newberryi, Mimulus pilosellus, Antennaria 
media, and Erigeron salsuginosus. 
