Some species of Mullein (_Verbascum_) are particularly partial to chalk and limestone districts. They are handsome plants, belonging to the order _Scrophulariaceæ_, rendered conspicuous by their woolly leaves and spikes of yellow or white flowers. The Great Mullein (_V. Thapsus_) is common on banks and roadsides, and flowers from June to August. Its stem is stout, erect, very woolly, and varies from two to five feet in height. The leaves are very large and thick, and are so woolly on both sides that they resemble flannel. The flowers form a large, dense, club-shaped spike. Each has a corolla with five spreading lobes; and five stamens, with white hairs on their filaments, two longer than the other three. The fruit is a capsule containing many seeds and splitting longitudinally. The White Mullein (_V. Lychnitis_) is not at all common, but may be found in similar situations. Its stem is angular, seldom more than three feet high, the leaves nearly smooth above, and the flowers white or cream, blooming from June to August. A third species--the Yellow Hoary Mullein (_V. pulverulentum_)--grows on banks, chiefly in Norfolk and Suffolk, flowering during July and August. It is about three feet in height; the stem is round, with a mealy surface; and the leaves, which are not continued down the stem, are covered both above and below with starlike hairs that give them a mealy appearance. The flowers form a pyramidal panicle, and are of a bright yellow colour, with scarlet stamens covered with white hairs. [Illustration: THE RED HEMP-NETTLE.] There is yet another species to be found on chalky soils, more especially in hedges and on banks and roadsides. It is the Dark Mullein (_V. nigrum_), so called on account of the darker hue of the stem and leaves. It grows to a height of about three feet and flowers from June to September. It is a beautiful plant, not so strong in build as the Great Mullein, with an angular stem, and oblong heart-shaped leaves, nearly smooth above, and covered with starlike hairs which give it a downy appearance, especially on the under surface. The leaves are not continued down the stem, and the lower ones have long stalks. The flowers are bright yellow, very numerous, and form a spike-like panicle. The stamens are covered with purple hairs. The Spiked Speedwell (_Veronica spicata_), of the same order, neither common nor widely distributed, is to be found chiefly in the chalk and limestone districts of the South and West of England, flowering during July and August. It has a long, dense, terminal spike of blue or pink flowers about a quarter of an inch in diameter. The corolla has a long tube, and unequal, narrow lobes; and the flattened capsules split into two valves when ripe. A large variety of this species, known as the Tall Spiked Speedwell, occurs in limestone districts of the West. The normal form is shown in Fig. 4, of Plate VIII.