Last updated October 1, 2009
| Name | Family | Nativity |
| Gaillardia cv. Goblin | Asteraceae | |
| Galvezia juncea cv. Gran Canon | Scrophulariaceae | |
| Gardenia thunbergia | Rubiaceae | South Africa |
| Gasteria armstrongii | Asphodelaceae | South Africa |
| Gasteria baylissiana | Asphodelaceae | South Africa |
| Gasteria bicolor cv. Frosty | Asphodelaceae | |
| Gasteria brachyphyllum | Asphodelaceae | South Africa |
| Gasteria brachyphyllum v. bayeri | Asphodelaceae | South Africa |
| Gasteria glomerata | Asphodelaceae | South Africa(E. Cape Prov.) |
| Gasteria nigricans v. monstrosa | Asphodelaceae | South Africa |
| Gasteria nitida v. armstrongii | Asphodelaceae | South Africa(E. Cape Prov.) |
| Gasteria sp. | Asphodelaceae | |
| Gaura cv. Siskiyou Pink | Asteraceae | |
| Gaussia maya | Arecaceae | Mexico, Guatemala, Belize |
| Gaussia princeps | Arecaceae | Cuba |
| Geijera parviflora | Rutaceae | Australia |
| Geranium incanum | Geraniaceae | South Africa |
| Geranium macrorrhizum | Geraniaceae | Europe |
| Geranium maderense | Geraniaceae | Portugal(Madeira) |
| Gerrardanthus Macrorhizus | Cucurbitaceae | South Africa, Mozambique |
| Ginkgo biloba | Ginkgoaceae | SE China |
| Gladiolus carmineus | Iridaceae | South Africa |
| Gleditsia sp. | Caesalpiniaceae | |
| Gleditsia triacanthus v. inermis cv. Sunburst | Caesalpiniaceae | |
| Glochidion sp. | Euphorbiaceae | |
| Goniophlebium subauriculatum cv. Knightii | Polypodiaceae | |
| Graptopetalum macdougallii | Crassulaceae | Mexico(Oaxaca) |
| Graptopetalum paraguayense | Crassulaceae | Mexico |
| Graptopetalum paraguayense ssp. bernalense | Crassulaceae | Mexico |
| Graptopetalum paraguayense ssp. paraguayense | Crassulaceae | Mexico |
| Graptopetalum pentandrum v. superbum | Crassulaceae | |
| Graptosedum cv. Alpenglow | Crassulaceae | |
| Graptoveria amethorum | Crassulaceae | |
| Graptoveria sp. | Crassulaceae | |
| Grevillea cv. Austraflora Fanfare | Proteaceae | |
| Grevillea cv. Canberra | Proteaceae | |
| Grevillea cv. Kay Williams | Proteaceae | |
| Grevillea cv. Poorinda Constance | Proteaceae | |
| Grevillea cv. Robyn Gordon | Proteaceae | |
| Grevillea cv. Ruby Clusters | Proteaceae | Australia(New South Wales) |
| Grevillea lanigera | Proteaceae | Australia |
| Grevillea lanigera | Proteaceae | S Australia |
| Grevillea lanigera cv. Coastal Gem | Proteaceae | |
| Grevillea paniculata | Proteaceae | W Australia |
| Grevillea robusta | Proteaceae | Australia |
| Grewia hispida | Tiliaceae | South Africa |
| Grewia occidentalis | Tiliaceae | South Africa |
| Greyia sutherlandii | Greyiaceae | South Africa |
| Griselinia littoralis | Cornaceae | New Zealand |
| Grusonia invicta | Cactaceae | Mexico(Baja Peninsula) |
| Guihaia argyrata | Arecaceae | S China |
| Guzmania lingulata hybrid | Bromeliaceae | |
| Guzmania patula | Bromeliaceae | Ecuador |
| Gymnocactus sp. | Cactaceae | |
| Gymnocalycium bayrianum | Cactaceae | Argentina |
| Gymnocalycium monvillei | Cactaceae | Argentina |
| Gymnocalycium oenanthemum | Cactaceae | Argentina |
| Gymnocalycium pflanzii | Cactaceae | Argentina, Bolivia |
| Gymnocalycium ritterianum | Cactaceae | Argentina(La Rioja) |
| Gymnocereus chlorocarpus | Cactaceae | Peru |
