786 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



The flora of the older or acid series will be first considered. Of the 

 79 species, 42 are either new to science or not specifically named, leaving 

 37 species having a distribution beyond the limits of the Park. Following 

 is a list of these species: 



Aspleuium erosuin (Lx.). Ulmus rhamnifolia Ward. 



Lygodiuiu kaulfusii (Heer). Eicus uugeri Lx. 



Taxites olriki Heer. Ficus asiminrefolia Lx. 



Sequoia couttsiai Heer. Laurus primigenia I Ung. 



Sequoia langsdorfii (Brgt.) Heer. Laurus priuceps Lx. 



Sparganium stygium Heer. Laurus californiea Lx. 



Cyperaeites angustior Al. Br. Laurus grandis Lx. 



Musopbyllum complicatum Lx. Ciunamonium spectabilis Heer. 



Juglans rugosa Lx. Platanus guillelina? Gopp. 



Juglans schimperi Lx. Leguminosites cassioides Lx. 



Myrica scottii Lx. Sapindus atiinis Lx. 



Populus glandulifera Heer. Sapindus alatus Ward. 



Populus speciosa Ward. Sapindus graudii'olius Ward. 



Populus dapknogenoides Ward. Paliurus colombi Heer. 



Salix lavateri Heer. Zizyphus serrulatus Ward. 



Fagus antipofli Heer. Tilia populiiblia Lx. 



Quercus consimilis Newby. Aralia notata Lx. 



Quercus olafseni Heer. Cornus uewberryi Hollick. 



These 37 species have the following distribution: Five are found in the 

 coal-bearing Laramie, 5 in the Denver and Livingston, 17, or nearly 50 per 

 cent, in the Fort Union, 9 in the Green River group, and 1 1 in the Aurifer- 

 ous gravels of California. Of the species common to the acid rocks and 

 the Laramie at Denver and Livingston beds, not one is found exclusively in 

 these beds, but they are such species as Sequoia langsdorfii, Juglans rugosa, 

 Platanus guillelnm, and Juglans schimperi, which enjoy a wide geological and 

 geographical distribution. 



The Fort Union element in this flora is a very important one ; in fact, 

 it may be called the dominant element, It includes at least 12 species that 

 have never before been found outside of the type locality. Among these 

 are Sparganium stygium, Populus speciosa, Populus dapknogenoides, Ulmus 

 minima, Ulmus rhamnifolia, Sapindus affinis, Sapindus grandifoliolus, and 

 Cornus newberryi. Some of these are represented by as many as 200 indi- 

 viduals, showing that they existed in great abundance, as they are also 

 known to have existed at the mouth of the Yellowstone. This abundance 



