The Woolly Willow (_Salix lanata_) is a small shrub, two or three feet high, with twisted branches, woolly twigs, and hairy black buds. The broad egg-shaped or oblong leathery leaves are also woolly, and two or three inches long. There are half-heart-shaped stipules at the base of the very short leaf-stalk. It is an Alpine plant, and is found about the mountain rills of Perth, Forfar, Inverness, and Sutherland at elevations between 2000 and 2500 feet. Conspicuous in spring for its rich golden catkins. Sadler's Willow (_S. sadleri_), of which only two or three specimens have been found (in Glen Callater, 2500 feet), is probably a form of this species.
The Lapland Willow (_Salix lapponum_) is of a similar proportion to the last-named, sometimes erect, sometimes trailing. Its leaves are more elliptic in shape, covered above with silky hairs and below with cottony filaments. In _lanata_ the raised veins form a network pattern; in _lapponum_ they are straight. The stipules at the base of the long foot-stalk are small or altogether wanting. Like the preceding species, it is restricted to Scotch Alpine rocks, at elevations between 2000 and 2700 feet.
The Whortle-leaved Willow (_Salix myrsinites_) is a small, wiry, creeping, or half-erect shrub, six inches to a foot high, with toothed, dark glossy leaves, an inch or less in length, whose net-veining shows on both sides. It is restricted to the Alpine parts of mid-Scotland, from 1000 to 2700 feet.
The Small Tree-Willow (_Salix arbuscula_) is a small shrub, whose stem creeps along the ground and roots as it goes, sending up more or less erect branches a foot or two high. The downy twigs are first yellow, then reddish-brown. The small leaves vary from egg-shaped to lance-shaped, and are shining above and glaucous beneath; toothed. In the Highlands of Aberdeen, Argyll, Dumfries, Forfar, and Perth, between 1000 and 2400 feet.
The Least Willow (_Salix herbacea_) is not so restricted in its range, for it is found in all parts of the United Kingdom where there are heights sufficiently Alpine (2000 to 4300 feet) for its tastes. It is only an inch or two high, and has consequently the distinction of being the smallest British shrub. It is not so herbaceous as it seems, or as its name implies, for its shrubby stem and branches creep along underground, sending up only short, scantly leaved twigs. The curled, roundish leaves do not exceed half an inch in length; they are net-veined, toothed, and shining. The catkins appear after the leaves.