Considering their extreme isolation, their uniform volcanic soil, and the large proportion of the chief island which consists of barren lava-fields, the flora of the Sandwich Islands is extremely rich, consisting, so far as at present known, of 844 species of flowering plants and 155 ferns. This is considerably richer than the Azores (439 Phanerogams and 39 ferns), which though less extensive are perhaps better known, or than the Galapagos (332 Phanerogams), which are more strictly comparable, being equally volcanic, while their somewhat smaller area may perhaps be compensated by their proximity to the American continent. Even New Zealand with more than twenty times the area of the Sandwich group, whose soil and climate are much more varied and whose botany has been thoroughly explored, has not a very much larger number of flowering plants (935 species), while in ferns it is barely equal. {322} The following list gives the number of indigenous species in each natural order. _Number of Species in each Natural Order in the Hawaiian Flora, excluding the introduced Plants._ DICOTYLEDONS. 48. Gentianaceae (Erythraea) 1 49. Loganiaceae 7 1. Ranunculaceae 2 50. Apocynaceae 4 2. Menispermaceae 4 51. Hydrophyllaceae (Nama ... 3. Papaveraceae 1 allies Andes) 1 4. Cruciferae 3 52. Oleaceae 1 5. Capparidaceae 2 53. Solanaceae 12 6. Violaceae 8 54. Convolvulaceae 14 7. Bixaceae 2 55. Boraginaceae 3 8. Pittosporaceae 10 56. Scrophulariaceae 2 9. Caryophyllaceae 23 57. Gesneriaceae 24 10. Portulaceae 3 58. Myoporaceae 1 11. Guttiferae 1 59. Verbenaceae 1 12. Ternstraemiaceae 1 60. Labiatae 39 13. Malvaceae 14 61. Plantaginaceae 2 14. Sterculiaceae 2 62. Nyctaginaceae 5 15. Tiliaceae 1 63. Amarantaceae 9 16. Geraniaceae 6 64. Phytolaccaceae 1 17. Zygophyllaceae 1 65. Polygonaceae 3 18. Oxalidaceae 1 66. Chenopodiaceae 2 19. Rutaceae 30 67. Lauraceae 2 20. Ilicineae 1 68. Thymelaeaceae 7 21. Celastraceae 1 69. Santalaceae 5 22. Rhamnaceae 7 70. Loranthaceae 1 23. Sapindaceae 6 71. Euphorbiaceae 12 24. Anacardiaceae 1 72. Urticaceae 15 25. Leguminosae 21 73. Piperaceae 20 26.