Another Lettuce, known as the Prickly Lettuce (L. Scariola), is somewhat rare. It is really less prickly than the last species, but is equally tall, and flowers during the same months. Its leaves are erect, lanceolate, sagittate, with a wavy margin; and the upper ones clasp the stem. The fruit of this species is of a greyish colour, and has a beak of the same length.
Two species of Sow-thistle (genus Sonchus) are included among our wayside Composites. They are erect, succulent plants, from two to three feet in height, with a milky juice, and either toothed or pinnatifid leaves. Their flower-heads are yellow, arranged in a corymb, and bloom during the whole of the summer. Each head is surrounded by several rows of overlapping bracts, and the receptacle is flat and pitted. The fruits are considerably flattened, without beaks; and the pappus consists of several rows of fine, silky, unbranched hairs.
The Prickly Lettuce.
One species is known as the Sharp-fringed Sow-thistle or the Common Milk-thistle (S. oleraceus). Its leaves are sometimes deeply divided, but always more or less toothed; and the teeth often terminate in sharp prickles. The upper ones clasp the stem, and have spreading, arrow-shaped ears. The stem is branched and hollow; and the fruit is ribbed and transversely wrinkled.
The second is the Common Sow-thistle (S. asper)—a very similar plant, but may be distinguished by its leaves, which are more spinously toothed, with rounded ears. In this one the fruits are also ribbed, but they are not wrinkled transversely.
The Smooth Hawk's-beard (Crepis virens) has a furrowed, branched stem, from a few inches to three feet in height. Its spreading radical leaves are deeply toothed, and narrower towards the base; and the stem leaves are narrow and sagittate. The numerous small heads of yellow flowers are panicled, and the outer florets are often tinged with red. The heads are surrounded by two rows of bracts, the outer of which are shorter and narrower, and the whole involucre assumes a conical form after flowering. The fruit is shorter than the pappus; tapering, but not beaked; and the pappus consists of several rows of unbranched, silky hairs. This plant flowers during July and August. It is very common on waste land, and may be frequently seen growing on old walls, and even on the roofs of country cottages and out-houses.
The Sharp-Fringed Sow-Thistle.
The genus Hieracium (Hawkweeds) is a puzzle not only to the beginner, but also to experienced botanists, who have not yet agreed as to its division into species. According to some authorities these latter amount to seven, but they, or rather some of them, are so variable, and present so many intermediate characters, that some botanists divide the British members into no less than thirty-three species.