We have next to note a few thistles that are more or less common on downs and moors, the first being the Musk Thistle (_Carduus nutans_), common in the South of England, but much less frequent in the North. It is a stout plant, usually scantily covered with a loose, cottony down, with a furrowed stem from one to three feet high. The leaves are very deeply divided pinnately, very prickly, and extend down the stem in the form of narrow, prickly wings. The flower-heads are very large, of a purple or crimson colour, drooping, usually solitary, but sometimes in loose clusters of from two to four. Each head is surrounded by numerous very narrow, stiff bracts, more or less covered with cottony down. All of these terminate in a sharp prickle which is erect on the inner bracts, but spreading or turned backward in the case of the outer ones. This thistle may be seen in flower from May to October. It appears on Plate VI, Fig. 1. The next species--the Dwarf Thistle (_Carduus acaulis_)--is found only in the southern and midland counties of England, but is very common on some of the elevated downs of the South-East, especially on chalky soils. It has a very thick and hard rootstock, but hardly any trace of a stem, so that its spreading tuft of radical leaves lie close on the ground, around the large, purple, stemless, and, usually, solitary flower-head. The plant flowers from July to September. [Illustration: THE CARLINE THISTLE.] The Carline Thistle (_Carlina vulgaris_), as its name shows, does not belong to the same genus as the others, from which it differs principally in having its inner bracts coloured and spreading. It is an erect plant, with a stiff stem, usually branching, from six to eighteen inches high. Its leaves are very prickly, and do not form wings down the stem. The flower-heads are particularly interesting, having much the appearance of everlasting flowers. In fact, the whole plant is of such a stiff and dry nature that it undergoes but little change in appearance when cut and preserved. The outer bracts are leafy and spreading, with strong, prickly teeth or lobes; and the inner ones are very narrow, entire, white or pale yellow, of a chaffy nature and very glossy. The latter are very sensitive to atmospheric conditions, spreading horizontally when the air is dry, and closing over the florets in humid air; and they respond so readily to the changed conditions that their movements may be watched as they are transferred from warm, dry air to a moist chamber, or _vice versa_. This plant is common on the downs of England and Ireland, and flowers from July to September. [Illustration: THE COMMON CHAMOMILE.]