26 



FOSSIL FORESTS OF YELLOWSTONE PAEK. 



such as a single large grass (Phragmites) , a few sedges (Cypera- 

 cites), a smilax, and a curious broad-leaved banana-like plant (Muso- 

 phyllum). The dicotyledons, or deciduous-leaved plants, make up 

 the bulk of the flora and include walnuts (Juglans), hickory nuts 

 (Hicoria), bay berries( Myrica), poplars (Populus), willows (Sa- 

 lix), birches (Betula), hazel nuts (Corylus), beech nuts (Fagus), 

 chestnuts (Castanea), oaks (Quercus), elms (Ulmus), figs (Ficus), 

 breadfruits (Artocarpus) , magnolias (Magnolia), laurels (Laurus), 

 bays (Persea), cinnamons (Cinnamomum) , sycamores (Plantanus), 

 acacias (Acacia), sumachs (Rhus), bittersweet (Celastrus), maples 

 (Acer), soap berries (Sapindus), buckthorns (Rhammus), grapes 

 (Cissus), basswood (Tilia), aralias (Aralia), dogwoods (Cornus), 

 persimmons (Diospyros), ash (Fraxinus), and a number of others 

 without vernacular names. 



COMPARISON WITH LIVING FORESTS. 



A bi'ief comparison of the fossil forests with the forests now living 

 in the Yellowstone National Park may be of some interest. The 

 jDresent forests are prevailingly coniferous, the most abundant and 

 widely distributed tree being the lodgepole pine {Pinus m^irrayana) ^ 

 which forms dense forests over much of the plateau region. It is 

 distinguished by having the leaves in clusters of two. It is a tree 

 with a slender trunk, usually 70 or 80 feet high, though in exception- 

 ally favorable localities it may reach a height of 150 feet. Its diam- 

 eter rarely exceeds 2 or 3 feet. The areas ravaged by forest fires are 

 usually reforested by this pine alone, and the young trees come up so 

 close together as to form thickets that can scarcely be penetrated. 



There are two other pines in the park, both white pines, allied to 

 the common white pine of the Eastern States, and like it both have the 

 leaves in clusters of 5. One, known as the Rocky Mountain white 

 pine {Pirn IS fexilis) is a small tree, only 40 or 50 feet in height, and 

 usually growls singly or in small groves. The other, called the West- 

 ern white pine {Pinus alhicaiilis) ^ is still smaller, being usually 20 

 to 30 feet high, and has a short trunk some 2 to 4 feet in diameter. 

 It grows on high slopes and exposed ridges. 



Perhaps next in abundance to the lodgepole pine is the white or 

 Engelmann spruce {Picea engelmanni) ^ a tall, handsome tree with 

 disagreeable smelling foliage. Another rather abundant tree is the 

 Douglas spruce, or red fir {Pseudotsugw mucronata) ^ which, where 

 best developed on the Pacific coast, attains a height of 200 feet, 

 though in the drier interior it is rarely over 80 or 100 feet high. 

 There are also two species of fir, the white fir {Ahies grandis) and 

 the Balsam fir {Ahies lasiocarpa) ^ and a single juniper {Juniperus 

 communis siherica) , which is often scarcely more than a shrub. 



