| Galium rzedowskii Dempster, 1975 |
| Galium seatonii Greenm., 1898 |
| Galium sphagnophilum (Greenm.) Dempster, 1973 |
| Galium sphagnophilum var. mazocarpum (Greenm.) Dempster, 1973 |
| Galium sphagnophilum var. sphagnophilum (Greenm.) Dempster, 1973 |
| Galium spurium L., 1753 |
| Galium stellatum Kellogg, 1863 |
| Galium trifidum L., 1753 |
| Galium triflorum Michx., 1803 |
| Galium uncinulatum DC., 1830 |
| Galium uropetalum Hemsl., 1881 |
| Galium volcanense Dempster, 1973 |
| Galium walteri J.F. Gmel., 1791 |
| Galium wigginsii Dempster, 1970 |
| Galium wrightii A. Gray, 1852 |
| Garapatica H. Karst., 1859 |
| Garapatica edulis H. Karst., 1859 |
| Gardenia J. Ellis, 1761 |
| Gardenia armata Sw., 1788 |
| Gardenia augusta Merr., 1917 |