All the plants of the group agree in the following particulars:—They have a milky sap. The leaves are nearly all radical. The flower-heads are either yellow or orange, surrounded by several rows of overlapping bracts. The receptacle is pitted. The fruit is not beaked, and its pappus consists of a single row of rigid, brittle, brownish hairs, which are simple and of unequal lengths.
One species at least is a common wayside flower, and this is the Shrubby Hawkweed (H. boreale). It grows from two to four feet high, and bears a corymb of many yellow heads, from July to September. Its stem is hairy below, downy with fine branched hairs above, and bears rigid, erect branches which are leafy, and often of a reddish colour. This species has no radical leaves. The stem leaves are ovate or lanceolate and toothed, the upper ones broad and slightly clasping the stem. The peduncle is scaly or woolly, and the involucre bracts are of a blackish green colour.
The Smooth Hawk's-Beard.
The Nipplewort (Lapsana communis) is another very common Composite of waysides and wastes. Its stem is erect, from one to two feet high, branched, armed with scanty stiff hairs below, and smooth above. The leaves are thin and usually hairy, the lower ones ovate, pinnatifid or coarsely-toothed, with a few smaller lobes along the stalks, and the upper ones small, and entire or only slightly toothed. The flower-heads are small, yellow, in a loose panicle with long slender stalks. The involucre consists of about eight glaucous scales, about a quarter of an inch in length, and a whorl of small outer ones. The fruits are flattened, with many longitudinal nervures, and have no pappus. The flowers may be seen from July to September.
The Chicory or Succory (Cichorium Intybus) is a local plant, but often very abundant where it exists. It has a long tap root; and a strong, erect, bristly and sticky stem. The lower leaves are spreading and hairy, deeply divided, with a large terminal lobe, and smaller lateral lobes which are pointed and coarsely toothed. The upper leaves are lanceolate, clasping the stem, with pointed auricles. The flower-heads are of a bright blue colour, large and conspicuous, mostly in sessile clusters of two or three along the rigid, spreading branches, but a few are terminal. The involucre consists of about eight inner bracts, and a whorl of outer ones that are much shorter. The florets are large; and the fruits are smooth, or nearly so, and closely enveloped in the lower part of the involucre. The time of flowering is from July to October.
The Nipplewort.
Our next species is the Burdock (Arctium Lappa), familiar as a wayside plant not only on account of its abundance and its large size, but also on account of its globular flower-heads which cling so tenaciously to our clothing by means of the hooked points of the inner involucre bracts. It is a very stout, branching plant, varying from two to six feet in height, with very large, stalked, cordate lower leaves that often exceed a foot in length. The upper leaves are smaller, and broadly ovate; and both these and the lower ones are smooth or nearly so on the upper surface, but often covered with a short white down beneath. All the leaves are also finely toothed, but bear no prickles. The flower-heads are in terminal panicles, and are surrounded by many bracts which are either quite smooth or covered with a white, woolly down. The florets are purple, and all equal in size. The fruits are large, and bear a short pappus of stiff hairs.
We now come to the interesting group of Thistles, all distinguished by their very hard stems; their cut or toothed leaves, which are generally very prickly; and their round or oval heads of flowers, surrounded by many whorls of overlapping, and usually prickly, bracts. There are no ray florets, but all are tubular and approximately equal in length.