This class, Tetradynamia, includes all the plants known as Crucifers (N.O. Cruciferae), on account of the petals being arranged like a cross. There are many genera, including such valuable plants as the cabbage, turnip, mustard and cress. The fruits are most useful for identification. Some are shaped like a pouch, as shepherd's purse; others (as the wallflower) form a long pod.

No.

Botanical Name.

Common Name.

Season.

Situation.

Structure and Habit.

95

Isatis .

Dyer's Woad.

July-Aug.

Fields . .

Yellow flowers, leaves on stems arrow-shaped.

96

Thlaspi

Penny Cress .

April-July

Fields . .

White flowers, large flat pouches. 3 species.

97

Capsella . .

Shepherd's

Purse

Feb.-Nov.

Wastes . .

One of the commonest of our weeds.

98

Teesdalia . .

Shepherd'sCress

April-June

Heaths . .

Leaves forming a rosette on the ground.

99

Cochlearia .

Scurvy Grass.

May-Aug.

Seaside .

White flowers, fleshy plant, pods globose.

100

Draba . . .

Whitlow . .

April-May

Banks . .

Often only 1 inch high, early flowering.

101

Camelina .

Gold of Pleasure

June-July

Fields . .

Rich yellow flowers, pods large on stalks.

102

Dentaria .

Coralwort. .

April-May

Woods . .

Li'ac, 1 or 2 feet high, bulbiferous, rare.

Cardamine

Lady's Smock

April -June

Meadows .

Lilac blossoms, often called cuckoo-flower.

103

Bitter Cress .

May-June

Marshes

White, anthers violet (C. amara, L.) (Fig. 22).

Impatience .

June-July

Rocks . .

White, pods snap when ripe and scatter seeds.

104

Barbarea .

Rocket

May-Aug.

Streams.

Yellow, with short pod thicker than stalk.

105

Clieiranthus .

Wallflower .

April-May

Walls . .

Flowers yellow, smaller than garden form.

106

Sinapis

Mustard .

May-Aug.

Fields . .

Yellow, pods spreading and knotty. Charlock.

IG7

Raphanus

Radish. . .

June-July

Fields . .

White or yellow, pods long and large.

There is but one plant in the British Flora, known as Trientalis, or winter-green, which has seven stamens, so we pass on to