St. John's-worts
What are they?
The St. John's-worts are temperate region representatives of a large family that also has tropical affinities. Typically they are short to medium, herbaceous perennials which have bright yellow, five-(sometimes four-)petalled flowers.
Where are they found?
These are plants of a wide range of habitats, though most grow in open, usually sunny, locales. Some species are more typically found in wetlands, while a few are found in woodland.
Identification
The species found locally are generally easy to identify from one another, but checking flowers and sepals for light or dark spots or streaks can be useful.
St. Peter's-wort Hypericum crux-andreae
Less common than the similar St Andrew's Cross and usually found in damp ground. Flowers July to September. Flowers flattened like those of St Andrew's Cross but leaves broader and stems winged.
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St. Andrew's Cross Hypericum hypericoides
Local but can be very common where it occurs, especially along woodland trails in the north of Cape May County. Flowers July to September. Flowers flattened, like those of St Peter's-wort but leaves narrower and stems rounded, not winged.
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Dense-flowered St. John's-wort Hypericum densiflorum
A woody sub-shrub which grows in old cranberry bogs and other boggy areas. Flowers July to September. Leaves are shiny and quite stiff, giving them an evergreen quality. The showy flowers are distinctive with their pompom of yellow stamens.
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Creeping St. John's-wort Hypericum adpressum
A low growing species of low, wet areas and marshland edge. Flowers July to August. Leaves rather long and narrow, like those of Dense-flowered St John's Wort, but they are soft and pliant, not stiff.
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Perforate St. John's-wort Hypericum perforatum
(Common St. John's-wort) An introduced species from Europe and - perhaps predictably - the most common St. John's-wort in our region. Common and widespread in open fields, roadsides and disturbed ground. The strange, translucent spots (which give the plant its name) in the leaves can be seen if held up to the light. Flowers June to September.
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& light dots |
translucent holes |
last into winter |
Spotted St. John's-wort Hypericum punctatum
A scarce plant of damp woodland paths, currently known from the lower part of the County. Flowers July to September.
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translucent holes |
Dwarf St. John's-wort Hypericum mutilum
A small species which favours the margins of wetlands and the edges of lakes and ponds. Though small, it often grows in sizeable colonies, studding the vegetation with tiny, bright yellow flowers. Flowers July to September.
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& hairless |
often broadly rounded |
Canadian St. John's-wort Hypericum canadense
A common species, widespread in wetland areas, though rather small and easily overlooked. Flowers July to September.
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| with narrow petals |
with rounded tips |
Orange-grass Hypericum gentianoides
Favors sunny, dry, usually sandy locations and often found where conditions are too dry for most other species. A strange member of the St. John's-wort family, with its leafless, rush-like stems. Flowers July to September.
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rush-like stems |
and pointed |
Coppery St. John's-wort Hypericum denticulatum
Found at scattered locations in open, grassy places. Flowers July to September. Despite the name, this species appears to me to be no more or less 'coppery' than other species in the genus!
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Virginia Marsh St. John's-wort Hypericum virginicum
Found in wet ground, usually in open, sunny spots on the edges of lakes and other more or less permanent wetlands. Flowers July to September. The coppery-pink tinge to the flowers makes this a readily-identified species.
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with rounded tips |