Petals white, rarely yellowish, reddish, or bluish. Fruit-valves with a faint middle-nerve. Seeds in one row.--Species 15. North, East, and South Africa. Some are used as ornamental plants. “Rock-cress.” =Arabis= L. 14. (7.) Median glands 4. Style 2-lobed; stigma dilated, not sharply limited. Fruit-valves convex or keeled. 15 Median glands 2, usually confluent with the lateral ones into a ring. Style short, truncate or somewhat depressed at the apex; stigma usually sharply limited. 16 15. Seeds flat; radicle accumbent.--Species 4. North Africa. Used as ornamental plants or in medicine. “Wallflower.” (Including _Dichroanthus_ Webb). =Cheiranthus= L. Seeds thick; radicle incumbent.--Species 5. North Africa to Abyssinia. Some are used as ornamental plants or in medicine. =Erysimum= L. 16. Partition of the fruit with two bundles of fibres; valves with a strong midrib. Radicle incumbent. Petals yellow. Leaves pinnatipartite.--Species 4. North Africa to Abyssinia. (Under _Sisymbrium_ L.). =Descurainia= Webb & Berth. Partition of the fruit without bundles of fibres. Petals white, rarely yellowish, reddish, or bluish. 17 17. Fruit-valves flat, with a faint middle-nerve. Seeds in one row; radicle accumbent. (See 13.). =Arabis= L. Fruit-valves more or less convex, with a strong middle-nerve. 18 18. Seeds with an accumbent radicle, in 2 rows.--Species 1. South Africa. (Under _Arabis_ L.). =Turritis= L. Seeds with an incumbent radicle, usually in 1 row.--Species 2. East, South, and North Africa, and Cape Verde Islands. (Under _Arabis_ L. or _Sisymbrium_ L.). =Stenophragma= Celak. 19. (2.) Fruit 1-seeded. 20 Fruit 2-or more-seeded. 22 20. Sepals petal-like. Petals reddish. Glands none. Ovary 3-celled. Style very short. Fruit elliptical, much compressed. Shrubs.--Species 1. South Africa (Cape Colony). =Schlechteria= Bolus Sepals not petal-like. Petals yellow or whitish. Glands present. Ovary 2-celled. Fruit orbicular. Herbs. 21 21. Filaments with a tooth-like appendage. Style none. Fruit flat, without a partition. Radicle accumbent. Fruit-stalk bent back. Leaves linear. Hairs star-shaped.--Species 2. North Africa. =Clypeola= L. Filaments not appendaged. Style thread-shaped. Fruit thick, with a rudimentary partition. Radicle incumbent. Fruit-stalk erect or spreading. Cauline leaves sagittate. Hairs 2-3-cleft.--Species 1. North Africa. Used medicinally. (_Vogelia_ Medik.) =Neslia= Desv. 22. Fruit 2-4-seeded. 23 Fruit many-seeded. 30 23. Petals yellow. 24 Petals white or reddish. 26 24. Sepals, at least the lateral, saccate at the base. Filaments without an appendage. Stigma 2-lobed. Fruit with laterally compressed, boat-shaped valves and a linear partition. Seeds 2-3; radicle incumbent. Shrubs. Leaves entire. Flowers solitary, axillary.--Species 1. Island of Socotra. =Lachnocapsa= Balf. Sepals not saccate. Herbs or undershrubs. Flowers in spikes or racemes. 25