21. Balsaminaceæ.—Herbs with simple, alternate leaves; and axillary, irregular, yellow flowers. Sepals 3 or 5, one forming a wide-mouthed spur. Petals 5, four of which are united in pairs. Stamens 5. Fruit a capsule with five elastic valves. (The Balsam Family.)
22. Oxalidaceæ.—Low herbs, with radical, generally trifoliate leaves; and axillary, regular flowers. Sepals 5. Petals 5, united at the base. Stamens 10. Ovary five-celled, with many ovules. (The Wood Sorrel Family.)
23. Celastraceæ.—Trees or shrubs, with opposite leaves; and small, regular flowers in axillary cymes. Sepals and petals usually 4. Stamens usually 4, alternating with the petals. Carpels 4. Fruit a fleshy capsule. (Spindle Tree.)
24. Rhamnaceæ.—Shrubs with simple leaves; small, greenish flowers; and berry-like fruit. Sepals, petals, and stamens 4 or 5. Stamens opposite the petals. Ovary superior, three-celled, with one ovule in each cell. (The Buckthorn Family.)
25. Leguminosæ.—Herbs or shrubs with alternate, stipuled leaves, generally pinnate or ternate, often tendrilled; and papilionaceous (butterfly-like) flowers. Sepals 5, combined. Petals 5, irregular. Stamens generally 10, all, or nine of them united. Ovary superior. Fruit a pod. (The Pea Family.)
26. Rosaceæ.—Trees, shrubs, or herbs with alternate, stipuled leaves; and conspicuous, regular flowers. Sepals 4 or 5. Petals 4 or 5. Stamens many. Carpels 1, 2, 5, or many. (The Rose Family.)
27. Onagraceæ.—Herbs with mostly entire, simple, exstipulate leaves; and conspicuous, regular flowers. Sepals 2 to 4. Petals 2 to 4, twisted in the bud, or absent. Stamens 2 to 4, or 8. Ovary inferior, with carpels 1 to 6 (usually 4), many-seeded. (The Willow-herb Family.)
28. Haloragiaceæ.—Aquatic herbs with whorled leaves and minute flowers. Sepals 2 to 4 or absent. Petals 2 to 4 or absent. Stamens 1, 2, 4, or 8. Ovary inferior. Carpels 1 to 4. (The Mare's-tail Family.)
29. Lythraceæ.—Herbs with opposite or whorled, entire leaves; and conspicuous, regular flowers. Sepals, and petals 3 to 6. Stamens generally twice as many as petals. Ovary superior. Carpels 2 to 6. Fruit a many-seeded capsule. (The Loosestrife Family.)