Our first example is the Welted Thistle (Carduus crispus or Carduus acanthoides), which is a common plant in the South of England, but much less abundant in the North. In general appearance it closely resembles the Musk Thistle (p. [266]), but is usually taller. The stem is covered with prickles which run downwards in lines from the bases of the leaves. The flowers are purple, in small, globular, clustered heads, which droop slightly; and the numerous bracts of the involucre are narrow, more or less erect, and terminate in a spreading or hooked prickle. The pappus consists of rough, unbranched hairs. The above is the description of the commonest form of this thistle, but it is a very variable species. The plants vary from one to three feet in height, and flower from June to August.
The Burdock.
Throughout the summer we may meet with the Spear Thistle (C. lanceolatus), a very abundant species which grows on almost all waste places. The plant is a stout one, varying from about one to five feet in height, with a winged, prickly stem. The leaves are cut into short, narrow lobes, with a long and pointed terminal one. They are covered above with stiff hairs, and below with a white down; and all the lobes terminate in stiff spines. The involucre is oval in form, covered with cottony down; and its bracts are lanceolate, terminating with a stiff, spreading spine. The flower-heads are few in number, with purple florets, and measure about an inch and a quarter in diameter.
The Spear Thistle.
Another common species is the Creeping Thistle (C. arvensis), which has a perennial, creeping rootstock that gives off erect annual stems from two to four feet in height. The stem is not winged, but the prickly leaves clasp it, and sometimes extend a little way down at their bases. The leaves are narrow, smooth, with edges turned inwards, very prickly, and cut into numerous narrow lobes. The flower-heads are small, arranged in loose terminal clusters, and are surrounded by numerous, closely-placed bracts with small, sharp points. The flowers are always imperfect, and the male and female blooms always occur on separate plants. The heads of the male plants are globular in form, with spreading purple florets; while those of the female plant are longer and almost cylindrical in form, with longer bracts and shorter florets. The pappus consists of numerous feathery hairs which grow very long as the fruit ripens. This species flowers during July and August.
The Tansy (Tanacetum vulgare) is common in the hedgerows of most localities, and is easily recognised by the powerful odour and bitter taste of its leaves and flowers. It has a creeping root; an erect, strong stem, which is either quite smooth or (generally) slightly downy; and large, pinnate leaves, with narrow, deeply-toothed or pinnatifid segments. There are a large number of flower-heads, nearly half an inch in diameter, of a bright yellow colour, and arranged in large flat-topped corymbs. This plant is common in most parts of Britain, grows to a height of about three feet, and flowers during August and September.
The Creeping Thistle.