The Common Whitlow Grass (_Draba verna_) is a very small and inconspicuous plant, abundant on banks and hedgerows, bearing minute, white flowers in April and May. It has a cluster of narrow, toothed, hairy, radical leaves, from a quarter to half an inch long, that spread horizontally close to the ground; and a leafless stem, from one to four inches long, bearing a raceme of flowers on slender pedicels. The petals of the flowers are deeply notched; and the fruits are oblong, about a quarter of an inch long and half that width, containing many seeds.
[Illustration: THE COMMON WHITLOW GRASS.]
Two species of Winter Cress (genus _Barbarea_) are common in waste land--the Common Winter Cress or Yellow Rocket (_B. vulgaris_), and the Early Winter Cress or American Cress (_B. præcox_). The former is an erect plant, from one to two feet high, with numerous, small, yellow flowers in a loose raceme, blooming from May to August. The radical leaves are pinnately divided, with a large, rounded, terminal lobe, and side lobes becoming smaller towards the base; and the upper leaves are oval and irregularly toothed. All the leaves are smooth and glossy, and of a deep green colour. The fruits are short, and thicker than the pedicels. A double variety of this flower is commonly cultivated in flower gardens.
The Early Winter Cress is a very similar plant, flowering at the same time, but is of a more slender habit, and has narrower leaves, the upper of which are pinnately divided. The flowers are also larger, and arranged in a closer raceme; and the fruit is longer, but not thicker than the pedicel. This species is cultivated as a salad, and frequently occurs as a garden escape.
Two species of _Sisymbrium_ are also very common--the Garlic Mustard (_S. alliaria_), also known as Sauce Alone and Jack-by-the-Hedge; and the Thale Cress or Wall Cress (_S. Thaliana_). The first named is one of the commonest of our hedgerow flowers. It grows to a height of one or two feet, and bears, from April to June, a corymbose cluster of pure white flowers, each about a quarter of an inch in diameter. The stem and leaves, when crushed, emit a distinct odour of garlic. The former is slightly branched; and the leaves are large, stalked, broadly cordate, with many prominent veins, coarsely toothed, and of a delicate green colour. The fruits are erect, about two inches long, on short pedicels.