xxv
KEY TO THE NATURAL ORDERS.
EXOGENS.
Stem with distinct wood, pith, and bark.
Leaves net-veined.
Embryo with 2 or more cotyledons.
Parts of the flower generally 2, 4, or 5, or their multiples—rarely 3 or its multiples.
Petals distinct. Stamens hypogynous.
* Stamens 12, or more.
1. Ranunculacæ. Ovary of 1 or more distinct carpels.
2. Nymphæaceæ. Aquatic plants. Petals passing into stamens towards the centre. Ovary many-celled.
4. Papaveraceæ. Herbs. Ovary of 2 or more carpels, 1-celled, with parietal placentas. Sepals falling when the flower opens.
8. Cistacæ. Small shrubs. Ovary of several carpels, 1-celled. Sepals permanent,
17. Hypericaceæ. Herbs or shrubs. Ovary many-celled. Leaves opposite, dotted. Stamens united into several groups.
15. Malvaceae. Herbs or shrubs. Ovary many-celled. Stamens united into a column.
16. Tillaceæ. Trees. Ovary many-celled, 1 -celled when in fruit. Stamens distinct.
7. Reesedaceæ. Herbs. Ovary 1-celled, opening at the top. Flowers irregular.
** Stamens under 12, filaments distinct,
† Flowers regular.
6. Cruciferæ. Herbs. Petals 4. Stamens 4 long and 2 short.
10. Droseraæ. Herbs with entire radical leaves cohered with glandular hairs.
2. Berberidaceæ. Herbs or shrubs. Stamens all opposite the petals. Ovary 1-celled. Anthers opening by recurved valves.
13. Caryophyllacæ. Herbs with jointed stems and opposite leaves. Placenta free and central.
12. Frankeniaceæ. Herbs. Stamens alternate with the petals. Sepals united. Placentas parietal.
18. Aceraceæ. Trees. Fruit 2-winged. Ovary 2-lobed, 2-celled.
22. Staphyleace. A shrub. Fruit bladder-like.
19. Geraniaceæ. Carpels 5, surrounding a long beak.
†† Flowers irregular.
9 . Violaceæ. Stamens 5. Ovary 1 -celled, opening by 3 valves.
20. Balsaminaceæ. Stamens 5. Ovary 5-celled.
*** Stamens under 12, filaments more or less connected at the base,
† Flowers regular.
14. Linaceæ. Stamens 4 or 5. Carpels 1- or 2-seeded, without a beak.
19. Geraniaceæ. Stamens 10. Carpels 5, surrounding a long beak. Style 1.
21. Oxalidaceæ. Stamens 10. Styles 5.
