TEEES AND SHRUBS. 



291 



Salicinece. There are only about eighteen distinct 

 species of Poplar, and all of them are confined to 

 north temperate regions. The following are the 

 most valuable, both from a purely economic point of 

 view and that of ornament also : — P. alba, the White 

 Poplar, or Abele, is a forest tree of the first magnitude. 

 Its leaves are clothed with a cottony down beneath, 

 and present a remarkable appearance when moved 

 by the wind. It is widely distributed throughout 

 Europe, North Africa, and Asia. P. a. nivea is a 

 form with leaves more distinctly white than the type, 

 and P. a. canescens, the Grey Poplar, is another, with 

 leaves ashy-grey beneath. P. a. Bolleana is a recently 

 introduced Asiatic form, of a pyramidal or fastigiate 

 habit — indeed, the counterpart, in this species, of 

 the Lombardy Poplar. P. angulata, the Angled 

 Cotton Wood of North America, has the twigs acutely 

 angled or winged, and broadly deltoid or heart- 

 shaped large leaves, with obtusely toothed carti- 

 laginous margins ; it is a fast-growing tree, attaining 

 a large size. P. balsamifera, the Balsam Poplar, or 

 Tacamahac. from the same country as the last-named 

 species, has round branches, with ovate, gradually 

 tapering and pointed, serrated leaves, smooth on both 

 sides; the large buds are covered with a copious, 

 fragrant, resinous matter, hence the specific name. 

 P. b. candicans principally differs from the typical 

 P. balsamifera in having the leaves whitish beneath. 

 P. grandidentata is another North American species ; 

 it is a medium-sized tree, with ovate-orbicular, 

 coarsely-toothed leaves ; a weeping variety is, per- 

 haps, more frequently grown than the type. P. 

 heterophylla, the Downy Poplar of the Eastern 

 United States, has round branches, long-stalked, 

 heart-shaped, or roundish-ovate leaves, which are 

 white -woolly when young, but nearly smooth 

 when mature ; it attains a height of from forty to 

 sixty feet ; there is a form with variegated leaves in 

 cultivation. P. nigra, the Black Poplar, is the one 

 which is perhaps most extensively planted in this 

 country ; it is a very fast-growing tree, with glabrous 

 shoots, glutinous buds, and triangular-ovate, acumi- 

 nate, serrated leaves. P. n. dilaiata, the Lombardy 

 Poplar, differs from the type principally in its erect 

 fastigiate habit. P. Eugenei is a valuable variety, 

 intermediate in habit between the typical Black 

 Italian and the Lombardy Poplars ; it originated as 

 a seedling in the famous nurseries of Messrs. Simon- 

 Louis freres, at Metz. P. tremula, the Aspen, is a 

 well-known indigenous tree, rarely attaining a height 

 of eighty feet, and is remarkable for the almost 

 constant quivering motion of its leaves ; a weeping 

 variety of this is a useful and very ornamental 

 tree. P. tremuloides, the American Aspen, is a 

 nearly-allied species, also represented in gardens by 

 a desirable weeping form. 



Prunus. — As it would be impossible to compress 

 within the space available an account of the dif- 

 ferent wild Plums from which our numerous garden 

 varieties have sprung, or, rather, are supposed to have 

 originated, only a few of the most distinct species 

 in this important genus are included. P. divaricata 

 is a slender-twigged species from the Caucasus, one 

 of the earliest to flower ; a good specimen on a lawn 

 seems in early spring to be clothed with a mantle of 

 snow, so profusely are the flowers produced ; not- 

 withstanding it rarely fruits in this country. P. 

 Myrobalana, an allied species from the same botanical 

 region, flowers somewhat later than P. divaricata, 

 but still earlier than most other Plums ; the fruits, 

 which are not often developed in Britain, are a fine 

 red colour, and about the size of a Cherry. It makes 

 a thoroughly good and ornamental hedge plant, and 

 thrives well in poor sandy or gravelly soils. P. Pis- 

 sardi, a beautiful variety of this, with rich-coloured 

 reddish - purple leaves, is a recent introduction 

 from Persia. P. Americana, the wild Yellow or Red 

 Plum of the Eastern United States, has a roundish- 

 oval fruit, varying from orange and yellow to red. 

 It is a thorny tree, from eight to twenty feet high, 

 perfectly hardy, and ornamental both in flower and 

 fruit. P. triloba, or, as it is sometimes called, 

 Amygdalopsis triloba, is a native of China and Japan, 

 and one of the most profuse, as well as one of the 

 most handsome, of early-flowering shrubs. It has 

 large, rose-coloured, double flowers, which come to 

 greater perfection if the plant be grown against a 

 wall. P. Sinensis flore-pleno is a dwarf compact grower, 

 best adapted of all those mentioned for growing in 

 pots. A very desirable shrub, too, is the double 

 form of the Sloe, P. spinosa, a dense-growing spiny 

 bush, laden in spring with double snow-white flowers. 



Ptelea trifoliata is the only species of this 

 genus of the Rue family worthy of mention here, per- 

 haps indeed the only one in cultivation ; it has long- 

 stalked, trifoliolate, glabrous, light green leaves, 

 which, as well as the fruits, emit a powerful odour 

 of Hops when bruised. A form with bright golden- 

 yellow foliage is one of the best of pictorial shrubs. 

 Both are quite hardy, and thrive in almost any soil 

 or situation. 



Pteroearya Caucasica is a handsome deciduous 

 tree, allied to the Walnuts, with large unequally 

 pinnate leaves. Planted near water, where its roots 

 can obtain an abundant supply of moisture, this 

 makes fine bold leaves, about a couple of feet in 

 length. It is certainly worthy of more extended 

 cultivation. 



Pyrus. — There exist about forty distinct species 

 in this genus, accepting the standard of specific rank 



