PINUS PONDEROSA. 365 



western slopes of the Sierra Nevada in the comparatively humid 

 climate of northern California where it attains its largest size ; and in 

 California it grows occasionally in wet and swampy ground. It is 

 the only Pine tree of Nebraska, and is very abundant on the Black 

 Hills of Dakota ; in northern Montana it forms a great forest in the 

 valley of the Flat Head Lake, and ranges westwards to the shores 

 of Puget Sound ; it dots the slopes of the eastern foot-hills of the 

 Rocky Mountains of Colorado, and clothes the divide between the 

 Platt and Arkansas rivers with a forest pushed far out over the 

 plain. Abundant in similar situations in Utah, and common on the 

 eastern slopes of the Sierras where it attains a great size and beauty, 

 P. ponderosa has found the climate of the Great Basin too severe for 

 it, and does not occur on the mountain ranges of central and southern 

 Nevada. The Colorada plateau which has an area of many thousand 

 square miles in southern Colorado and Utah and in northern Mexico and 

 Arizona, is covered with a forest of this tree. This is now the 

 greatest uninterrupted Pine forest of the continent, and one of the 

 largest in the world. South of the Colorado plateau the desert is 

 broken up into short ranges of mountains, and on them on both sides 

 of the Mexican boundary P. ponderosa is a common tree, as it is on 

 the mountains of western Texas. 



A tree of such enormous range over a region of so many different 

 climates has naturally developed many forms, and no other American 

 Pine tree varies more in size and habit, in the character of the bark, 

 length of leaves and size of cones. Sometimes it is 250 feet high, 

 with a trunk 12 feet in diameter covered with bright cinnamon-red 

 bark broken into great plates ; sometimes it attains with a difficulty 

 a height of 50 feet, and its bark is nearly black and deeply furrowed. 

 Such variations in the character of the bark are not always due to 

 climate, and individuals with the red bark of the Calif ornian tree and 

 the black bark of the inhabitant of the arid slopes of the Colorado 

 mountains stand side by side in northern Arizona, to the discouragement 

 of the botanist anxious to understand this tree and the causes of its. 

 variations. One hundred photographs would not be too many to illustrate 

 the appearance of Pinus ponderosa in the different parts of the country 

 which it inhabits ; and an attempt to describe the different forms, 

 with any words at our command would be hopeless. Certain characters 

 which botanists consider valuable specifically can be found in all the 

 forms, so that it is most convenient to consider them all geographical 

 varieties of one species, although in size and general appearance and 

 in the character and value of the timber produced, they are as distinct 

 as many of the recognised species of our Pines. 



Pinus ponderosa first became known to science and arboriculture 

 through David Douglas during his first mission to north-west 

 America, and by whom seeds were sent to the Horticultural Society 

 of London in 1827, from which a number of plants were raised and 

 distributed among the Fellows.* Douglas had discovered the tree 



* One of these may still be seen at Dropmore towering to a height of 90 feet ; this 

 is probably the largest specimen in this country. There is a fine tree over 60 feetjiigh 

 at Orton Hall, Peterborough ; another about the same height but denuded of its 

 lowermost branches at Lin ton Park, Maidstone ; and a still larger one at Barren Hill, 

 Anglesey. Trees of smaller dimensions are growing at Revesby Abbey, Whittinghame-. 

 in East Lothian, Scone Palace, Oastle Kennedy, etc. 



