564 Part IV. Chapter 3. 
the herbs: Antennaria nardina, Senecio crocatus, Carex capillaris, and as secondary species: Juncus 
triglumis, J. castaneus. 
Alpine Mat Formation. The facies of this formation early in the 
season is Paronychia pulvinata, Silene acaulis, Arenaria sajanensis, Erigeron 
pinnatisectus, Actinella. (Tetraneuris) lanata and the principal herbs associated 
with above in this formation are 7; rifolium dasyphyllum, Carex petasata 
(= C. leporina), Zygadenus elegans, Polygonum bistortoides, Pentstemon Halli, 
Agropyrum Scribneri, Sieversia turbinata var. nana, Potentilla minutifolia with 
the following as secondary elements of the early season: Sarıfraga austro- 
montana, Phacelia Lyallii, Festuca brevifolia (= F. brachyphylla). Later in the 
season the presence of Senecio taraxacoides, Potentilla fruticosa var. tenuifolia 
changes the facies and the principal herbs at that time of the year are: 
Macronema pygmaea, Trisetum subspicatum, Calamagrostis purpurascens and 
associated with them are: Sedum stenopetalum, Arenaria (Alsine) verna var, 
aequicaulis. Only one fern occurs, viz: Cryplogramma acrostichoides. — 
Timber line is reached on Pikes Peak at approximately 11,500 feet (3500 m). 
The plants characteristic of the treeless alpine belt are Senecio Fremontii, Artemisia 
scopulorum, Mertensia a: Eritrichium argenteum, Paronychia pulvinata, Silene acaulis, 
Claytonia megarrhiza, a Parryi, Salix reticulata (= S$. saximontana) Saxifraga cernua, 
Gilia sp., Oxyria Bra; Chionophila Jamesi, Trifolium dasyphylium, T. nanum, Dryas octo- 
petala, Erigeron uniflorus, Solidago multiradiata, Saxifraga rhomboidea, S. a Campanula 
uniflora, Pentstemon Halli, Cymopterus (Oreoxis) alpinus, Caltha leptosepala (= C. rotun difolia). 
— High upon Mount Lincoln, Colorado at 14,000 feet (4270 m) where found the following 
plants of nie eg Silene et Sign: caroliniana, var. lanceolata, C. aretiea 
var. megarrhiza, with its deep, purple tap root running deep into the rocks and its scape with 
white flowers, li a T. nanum, y. dasyphyllum, T. Parryi, Eritrichium (Omphalodes) 
aretioides 
On the high alpine crest at the head of Stinking Water, overlooking to the west the 
Yellowstone basin and lake!) the flora je the usual dwarf forms of high alpine summits, 
viz: Arabis Drummondii, Arabis canescen a alpina, Smelowskia calycina, Arenaria arctica, 
Ivesia (Horkelia) Gordonii, Potentilla Aare Br alpinus, A. Kentrophyta (= Ho malobus 
moment), Lupinus AMEIENIIh, Sedum RUEHORECEINEN, Erigeron compositus, Senecio canus, Achillea 
Eri 
e ind swept summit of Mount Holmes in the Vellowstone Park is characterized 
by the ee of Douglasia She Salix reticulata, Draba crassifolia, D. alpinay 
 Smelowskia calycina, Arenaria Michauxü (= A. strieta), Silene acaulis, Saxifraga oppositi- 
folia, Oxytropis Lamberti, Astragalus tegetarius var. implexus, Dryas octopetala, Sibbaldia 
procumbens, Antennaria alpina, Artemisia scopulorum, Erigeron uniflorus, E& 
radicatus2). 3 
Alpine Rockfield Formation. According to CLEMENTS, the exposed rock : 
areas where boulders are found, or where the surface is bare and stony, fr“ 
characterized early in the season by a facies of Polemonium speciosum = P : 
humile), ar sent BEREPUER ereiica var. negarrhisa, Boykinia James, 
1) Parrv, C. C.: Botanical Observations in western Wyoming. American Naturalist var: cr. 
2) Tweeov, FRANK: Notes on the Flora of Vellowstone Park. Bulletin Torrey Botanical 
Club XI: 2 
