414 THE CATKIN FAMILY. [Salix. 



inch long, finely crenated, green, glabrous, and veined like those of 

 S. Myrsinites, or sometimes slightly silky-hairy when young. Catkins 

 very small, ovoid, and few-flowered, on very short, leafless peduncles, 

 or almost sessile, opposite the last leaf of the young shoots. In fruit 

 they sometimes attain half an inch. Capsules nearly glabrous, fully 2 

 lines long. 



In alpine pastures, in northern and Arctic Europe and Asia, and in 

 the Alps and Pyrenees. Common at high elevations in the mountains 

 of Scotland, northern England, North Wales, and Ireland. FL simmer. 



IX. POPULUS. POPLAE. 



Leaves usually broadly triangular or nearly orbicular, on slender 

 stalks, the scales of the leaf -buds often covered with a resinous varnish. 

 Catkins cylindrical, usually silky-hairy, the scales irregularly toothed 

 or lobed at the top. Perianth (or inner united scales) a small, flat, 

 oblique cup. Stamens in the males from about 8 to near 30, with 

 slender filaments and small 4 anthers. Ovary in the females 1-celled, 

 with several ovules inserted on short, parietal placentas. Styles 2, 

 with deeply forked stigmas. Fruit a capsule, opening in 2 valves. 

 Seeds several, minute, with a tuft of long, silky hairs. 



A small genus, confined to the temperate regions of the northern 

 hemisphere, very near the Willows in flowers and fruit, but distinct in 

 habit and foliage, and in the presence of an apparent perianth. 



Under side of the leaves and young shoots very white and cottony 1. P. alba. 

 Under side of the leaves green and glabrous. 

 Leaves ovate-triangular, tapering at the top, with small, regular 



teeth . . 3. P. nigra. 



Leaves small, orbicular or rhomboidal, irregularly and rather 



coarsely toothed 2. P. tremula. 



The Tacamahac or balsam Poplar (P. balsamifera), the Carolina Poplar 

 {P. angulata), and other North American species, are often planted. 



1. P. alba, Linn. (fig. 933). White P., Abele. — A tall and handsome 

 tree, with a light-grey or ash-coloured bark, the young shoots, as well 

 as the under side of the full-grown leaves, covered with a close, very 

 white cotton. Leaves orbicular or very broadly ovate, irregularly 

 sinuate or shortly lobed, more or less cordate at the base. Catkins 

 sessile, about 2 inches long, the membranous scales jagged at the top, 

 very deciduous, hairy in the males, less so in the females. Stamens 

 usually about 8. Lobes of the stigmas linear. 



Along streams, and in open, moist woods, dispersed over central and 

 southern Europe and temperate Asia. In Britain, very generally planted, 

 and probably also indigenous. PL spring. P. canescens is a variety [or 

 hybrid with P. tremula] with rather smaller leaves, seldom lobed, and 

 not so white. 



2. P. tremula, Linn. (fig. 934). Aspen. — A smaller tree than our 

 two other Poplars, of slower growth, the branches more slender. Leaves 

 nearly orbicular, like those of P. alba, but smaller, often not an inch 

 broad, less deeply toothed, scarcely cordate, of a thinner texture, with- 

 out any white cotton, although sometimes very pale underneath ; the 

 leafstalks particularly slender, so that the blade trembles with the 

 slightest motion of the air. Catkins much smaller than in P. alba t the 



