480 THE CATKIN FAMILY. 



sessile, opposite the last leaf of the young shoots. In fruit they sometimes 

 attain half an inch. Capsules nearly glabrous, full 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 Scot- 

 land, extending into northern England, North Wales, and northern Ireland. 

 Fl. summer. 



IX. POPLAR. POPULUS. 



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 sUky-hairy, the scales irregularly toothed or lobed at 

 the top. Perianth (or inner united scales) a small, flat, obhque cup. 

 Stamens in the males from about 8 to near 30, with slender filaments and 

 small 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 hemi- 

 sphere, very near the Willoios 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. White JP. 

 Under side of the leaves green and glabrous. 



Leaves ovate-triangular, tapering at the top, with small, regular teeth 3. Slack P. 



Leaves small, orbicular or rhomboidal, irregularly and rather coarsely 



toothed 2. Aipen P. 



The Tacamahac or balsam P. (P. ialsamifera), the Carolina P. (P. an- 

 ffulata), and some other North American species, are to be met with in our 

 plantations. 



1. VHiite Poplar. Populus alba, Linn. 

 (Eng. Bot. t. 1618. Abele.) 



A tall and handsome tree, with a hght-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, irre- 

 gularly 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 hnear. 



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

 southern Europe and temperate Russian Asia, scarcely extending into north- 

 ern Germany. In Britain, very generally planted, and probably truly indi- 

 genous in eastern and southern England. Fl. S'pring. The grey P. (P. 

 canescens, Eng. Bot. t. 1619) is a variety with rather smaller leaves, seldom 

 lobed, and not so white. 



2. Aspen Poplar. Fopulus tremula, Linn. 



(Eng. Bot. t. 1909. Aspen.) 



A smaller tree than our two other Poplars, of slower growth, the branches 



more slender. Leaves nearly orbicular, hke those of the white P., but 



smaller, often not an inch broad, less deeply toothed, scarcely cordate, of a 



thinner texture, without any white cotton, although sometimes very pale 



