| NAME OF PLANT | WHERE FOUND | DATE | WHERE FOUND | DATE |
| Humulus lupulus | ||||
| hop | ||||
| Huperzia selago | ||||
| fir clubmoss | ||||
| Hyacinthoides hispanica x H. non-scripta | ||||
| hybrid bluebell | ||||
| Hyacinthoides non-scripta | ||||
| bluebell | ||||
| Hydrocharis morsus-ranae | ||||
| frogbit | ||||
| Hydrocotyle ranunculoides | ||||
| floating pennywort | ||||
| Hydrocotyle vulgaris | ||||
| marsh pennywort | ||||
| Hymenophyllum wilsonii | ||||
| Wilson's filmy fern | ||||
| Hyoscyamus niger | ||||
| henbane | ||||
| Hypericum androsaemum | ||||
| tutsan | ||||
| Hypericum calycinum | ||||
| rose-of-Sharon | ||||
| Hypericum elodes | ||||
| marsh St John's-wort | ||||
| Hypericum hirsutum | ||||
| hairy St John's-wort | ||||
| Hypericum humifusum | ||||
| trailing St John's-wort | ||||
| Hypericum maculatum | ||||
| imperforate St John's-wort | ||||
| Hypericum montanum | ||||
| pale St John's-wort | ||||
| Hypericum perforatum | ||||
| perforate St John's-wort | ||||
| Hypericum pulchrum | ||||
| slender St John's-wort | ||||
| Hypericum tetrapterum | ||||
| square-stalked St John's-wort | ||||
| Hypochaeris radicata | ||||
| cats'-ear | ||||
| 43 | ||||