June 15, 1892.] 



Garden and Forest. 



277 



GARDEN AND FOREST. 



PUBLISHED WEEKLY BY 



THE GARDEN AND FOREST PUBLISHING CO. 



Office: Tridune Building, Nkw York. 



Conducted by Professor C. S. Sargent. 



ENTERED AS SECOND-CLASS MATTER AT THE POST OFFICE AT NEW YORK, N. V, 



NEW YORK, WEDNESDAY, JUNE 15, 1892 



TABLE OF CONTENTS. 



PAGE. 



Editorial Articlhs : — American Poplars. (With fij^ure) 277 



Tiie General Design of the Cohimbian Fair Grounds 278 



Questions for American Botanists 278 



The Flower-trade of Paris 279 



The Time of Roses Mrs. Danske Dandridge. 279 



New ok Little-known Plants : — A New Water-lily 280 



Foreign Correspondence : — A Visit to Mount Salvatore in May, 1892.,//. Christ. 280 



Cultural Department ; — Notes on Shrubs y, G. yack. 282 



Hardy Narcissi. — II O. 283 



Natural Varieties of Narcissus Tazetta W. E. Endicott. 283 



The Water-garden y. N. G. 283 



Notes from the Harvard Botanic Garden AI. Barker. 284 



The Pear Psylla E. G. L. 285 



Correspondence : — The Color and Form of Houses S. P. S. 285 



A May Outing F. y. Le Moyne. 286 



American Species of Ash Alfred Wesviael. 286 



Hardy Plants at Passaic, New Jersey y. 286 



Recent Publications 287 



Notes 287 



Illustration : — A Group of Populus trichocarpa in the Vosemite Valley, Fig. 52. . 281 



American Poplars. 



THE genus Populus is not a large one, although the 

 species are widely scattered, and no other trees, 

 perhaps, play a more important part in the economy of 

 nature. Poplars are not easy to understand, although, like 

 the Willows, to which they are closely related, the struc- 

 ture of the flowers is very simple. The two sexes, how- 

 ever, are separated on different plants, and individuals 

 show a perplexing tendency to vary in habit and in the 

 form of the leaves, while natural hybridization increases 

 the difficulties of the student, who finds among them, too, 

 uncertain varieties of unknown origin long known in 

 cultivation. 



Poplars grow in the boreal parts, on the mountain- 

 ranges, and by the banks of midcontinental streams in both 

 northern hemispheres, and often attain a large size in 

 places where no other tree can exist. They are able to 

 support intense cold and great atmospheric dryness if 

 their roots can reach water ; their light seeds are produced 

 in immense quantities, and, furnished with an appendage 

 of buoyant hairs, are blown far and wide in spring and 

 early summer, and reaching the ground, while it is still 

 moist, germinate quickly, while broken branches carried 

 by wind or water often root when they reach the ground. 

 Poplars, therefore, are unusually well equipped with means 

 for multiplication, and are able to spread over large areas 

 where less favored trees cannot obtain a foothold. 



In North America eight species at least may be dis- 

 tinguished ; the most valuable of them, although the 

 smallest, is the so-called Quaking Aspen (Populus tremu- 

 loides), a tree very similar, to the Old World Aspen (Popu- 

 lus tremula). The value of this little short-lived tree, which 

 rarely attains the height of fifty feet, is not in the wood it 

 produces, for this is small and of no value except in paper- 



making, but lies in the power of its seed to germinate in 

 burnt soil and in the rapidity with which the young seed- 

 lings grow and cover exposed surfaces of bare ground. 

 By holding the soil on mountain-slopes and affording 

 shelter for the seedlings of longer-lived and more valuable 

 trees the Aspen has played a conspicuous part in the per- 

 petuation of forests, and no other plant, perhaps, from the 

 time it appeared in direct descent from a familiar type of 

 the tertiary Arctic flora to the present day has had so great 

 an influence in the composition and distribution of the 

 subalpine and boreal forests of North America. In its 

 present form the American Aspen ranges from Newfound- 

 land to Labrador and Alaska, and southward through the 

 northern states, and over mountain-ranges of the interior of 

 the continent, where it ascends almost to the upper limits 

 of tree-growth, marking steep and barren slopes with 

 broad light-green splashes, which in autumn glow like 

 gold against the dark background of rocks and stunted 

 Pines. 



A tree of larger size and of circumpolar distribution, for 

 it is common in Europe and Asia as well as in America, is 

 Populus balsamifera, commonly called in this country 

 Balsam and Balm of Gilead, because the buds are covered 

 with a resinous balsamic exudation which is sometimes 

 used medicinally by rural practitioners. In America this 

 fine tree ranges from the shores of the Straits of Belle 

 Isle to Alaska, and southward to within the northern bor- 

 ders of the United States. It is very common in British 

 America, where on low sandy river-plains and islands 

 it constitutes forests of considerable extent and plays an 

 important part in controlling and directing the drainage of 

 a vast territory. In cultivation the Balsam is a handsome 

 tree, especially the variety Candicans, of uncertain origin, 

 which is distinguished by its large leaves, pale or nearly 

 white on the lower surface ; it is very hardy, it grows with 

 surprising rapidity, and in cold countries no tree will 

 attain to a large size in so short a time. Like other Pop- 

 lars, however, the branches are brittle and easily broken, 

 and the trunk is often injured by boring insects which 

 prey upon all the trees of this genus, especially when they 

 are isolated in cultivation or planted in too warm a climate 

 or in too dry soil. 



Closely related to the northern Balsam is a tree of west- 

 ern America, where it ranges from British Columbia to 

 southern California. This is the Populus trichocarpa of re- 

 cent authors, who find in its pubescent ovaries and fruit 

 sufficient reason of its specific distinctness. The western 

 Balsam is one of the tallest of the genus, and individuals 

 approaching two hundred feet in height, with tall, slender 

 stems, are not rare at the north, where it forms handsome 

 open groves by river-banks at low elevations, while at the 

 south it seeks a cool and humid atmosphere by climbing into 

 mountain canons, which it decorates between four thousand 

 and six thousand feet above the sea-level. In the picture 

 on page 281 of this issue, taken from a photograph made by 

 Dr. William H. Rollins, appears a vi-ell-known grove of the 

 western Balsam on the banks of the Merced River in the 

 Yosemite Valley, from which our readers can gain a good 

 idea of the general appearance and manner of growth of 

 this tree in central and northern California, where it does 

 not attain such a large size as it often does in Oregon and 

 Washington. 



The familiar Cottonwoods which line the banks of the 

 great rivers and of the scanty and uncertain streams of the 

 central and south-western parts of the country are Poplars, 

 whose bright green foliage and grateful shade have cheered 

 the hearts and excited the imaginations of thousands of 

 worn and discouraged travelers on the plains and deserts 

 of western America. To three trees, the name of Cotton- 

 wood due to the white silky hairs attached to the seeds, 

 has been indiscriminately given. The first of these is 

 the Carolina Poplar (Populus monilifera), an inhabitant 

 of river-banks in all the country from eastern New Eng- 

 land and northern Florida to the eastern base of the Rocky 

 Mountains; it is the common Cottonwood of the streams 



