Rare plants, such as touch-me-not balsam Impatiens noli-tangere and alpine enchanter's-nightshade Circaea alpina, also have important British occurrences here.
The leaves of jewelweed (Impatiens spp.), which often grows near poison ivy, may neutralize the poison-ivy allergen if rubbed on the skin right after contact.
Conversely, although full sun throughout the yard sounds like paradise, other gardeners may want to add raised beds in shady areas to grow ferns, astilbe, impatiens and other flowers that love shade.
In respect to positive affinities, Sir Joseph Hooker pointed out some relations with the flora of tropical Africa as evidenced by the prevalence of such genera as Grewia and Impatiens, and the absence, common to both countries, of oaks and pines which abound in the Malayan archipelago.