27. (19.) Ovary 2-5-celled, with 1-2 ovules in each cell. Stamens twice as many as the petals. [Subtribe LIMONIINAE.] 28 Ovary 5-or more-celled, with 4 or more ovules in each cell. Leaves with 1-3 leaflets. [Subtribe CITRINAE.] 32 28. Ovules solitary in each ovary-cell. 29 Ovules two or more in each ovary-cell. Unarmed plants. 30 29. Flowers solitary or in groups of three in the axils of the leaves, 3-, rarely 4-merous. Calyx toothed. Seeds usually with unequal and lobed cotyledons. Spiny shrubs. Leaflets 3, unequal.--Species 1. Cultivated in the tropics. Yields timber, fragrant flowers, and edible fruits. =Triphasia= Lour. Flowers in racemes or panicles, 4-5-merous. Calyx lobed or more deeply divided. Leafstalk winged.--Species 10. Tropics. They yield timber, edible fruits, oily seeds, and medicaments. =Limonia= L. 30. Style very short, not jointed with the ovary. Leaves unifoliolate.--Species 1. West Africa. =Glycosmis= Correa Style long or rather short, jointed with the ovary. Leaves unequally pinnate. 31 [Illustration: RUTACEAE. _FLOW. PL. AFR._ _Pl. 73._ J. Fleischmann del. Agathosma ciliata Link _A_ Flowering branch. _B_ Flower. _C_ Petal. _D_ Stamen. _E_ Staminode. _F_ Flower cut lengthwise. _G_ Cross-section of ovary. _H_ Fruit.] [Illustration: SIMARUBACEAE. _FLOW. PL. AFR._ _Pl. 74._ J. Fleischmann del. Irvingia Barteri Hook. fil. _A_ Flowering branch. _B_ Flower cut lengthwise. _C_ Cross-section of ovary.] 31. Filaments awl-shaped. Petals 5, linear lanceolate or oblong. Flowers rather large.--Species 1. Cultivated and naturalized in the tropics. Yields timber, fragrant flowers, and medicaments. =Murraya= L. Filaments broadened below. Petals 4-5, elliptical or roundish. Flowers rather small.--Species 6. Central and South Africa. Some are used medicinally. (Including _Myaris_ Presl). =Clausena= Burm. 32. Ovary with 4-8 ovules in each cell. Anthers oblong. Pericarp leathery. Seed-coat white, leathery. Leaves leathery.--Species 4. Cultivated; also naturalized in the tropics. They serve as ornamental plants and afford wood, fragrant flowers, and edible fruits (especially oranges and citrons) from which drinks, medicaments, and perfumes are prepared. =Citrus= L. Ovary with numerous ovules in each cell. Anthers linear. Pericarp hard. Leaves with 3 leaflets. 33 33. Stamens 10. Seed-coat smooth. Leaves leathery.--Species 1. Region of the great lakes. =Balsamocitrus= Stapf Stamens numerous. Seed-coat woolly and sticky. Leaves herbaceous.--Species 1. West Africa. Yields timber and is used in medicine. =Aegle= Correa FAMILY 116. SIMARUBACEAE