TRAILING ST. JOHN'S-WORT

Hypericum humifusum

St John's Wort Family [Hypericaceae]

month8jun month8june month8jul month8july month8aug month8sep

status
statusZnative
flower
flower8yellow
morph
morph8actino
petals
petalsZ5
stem
stem8round
stem
stem8ribbed
toxicity
toxicityZlowish

27th Aug 2006, heathland, Warden Point Holiday Centre, IoW. Photo: (CC by 2.0) Geoff Toone
This specimen is less sprawling than the Glenridding example and a little more upright. On a sandy soil here. It is a hairless perennial.


27th Aug 2006, heathland, Warden Point Holiday Centre, IoW. Photo: (CC by 2.0) Geoff Toone
The stems are up to 20cm long.


27th Aug 2006, heathland, Warden Point Holiday Centre, IoW. Photo: (CC by 2.0) Geoff Toone
The stems have two lines on opposite sides. Leaves are less than 15mm long and either ovate or obovate or oblanceolate or lanceolate.


26th Sept 2008, Greenside Mines, Glenridding, Cumbria Photo: © RWD
One of the five or six that prefers acid soils and the only prostrate sprawling St. John's Worts barely reaching 20cm in height.


26th Sept 2008, Greenside Mines, Glenridding, Cumbria Photo: © RWD
About half the St. John's Worts are bright yellow rather than Pale yellow, and this is one of them.


10th July 2009, Seathwaite, Borrowdale, Cumbria. Photo: © RWD
The thin wiry stems are un-able to hold much of the plant upright.


26th Sept 2008, Greenside Mines, Glenridding, Cumbria Photo: © RWD
With pale green leaves in opposite pairs.


10th July 2009, Seathwaite, Borrowdale, Cumbria. Photo: © RWD
With black dots both on the edges of the petals, and on the sepals. Sepals less than twice as long as petals.


26th Sept 2008, Greenside Mines, Glenridding, Cumbria Photo: © RWD
Five rich yellow oval petals with black dots (either stalked, or sessile) on their periphery. Un-opened buds are reddish.


10th July 2009, Seathwaite, Borrowdale, Cumbria. Photo: © RWD
Up to 15 or so stamens bearing risc-yellow pollen. Spherical ovary in centre has three styles.


10th July 2009, Seathwaite, Borrowdale, Cumbria. Photo: © RWD


26th Sept 2008, Greenside Mines, Glenridding, Cumbria Photo: © RWD
The flowers are between 8 and 12mm across.


26th Sept 2008, Greenside Mines, Glenridding, Cumbria Photo: © RWD
Un-opened flower-bud.


26th Sept 2008, Greenside Mines, Glenridding, Cumbria Photo: © RWD
The black glands on the leaves are only sparsely present on the sepals and petals and are either unstalked or stalked.


Superficial resemblance to : Trailing Tormentil which can sometimes have flowers with five petals. It too has yellow flowers and trails close to the ground, but the leaves are trefoil and the petals heart-shaped.

Uniquely identifiable characteristics

Distinguishing Feature :

No relation to : Trailing Bellflower, Trailing Snapdragon, Trailing Tormentil or Trailing Azalea, [plants with similar names from differing Families].

It is said to have two thin narrow ridges running lengthways on opposite sides of the stems, but your Author thinks you have to have a bit of imagination to actually see them in photographs.

It grows in open woods and dry heaths, preferring acidic soils as evidenced in the above photographs where it is accompanied by reeds and mosses.

The stems yield a brown-red dye when alum is used as the mordant. The flowers, on the other hand, yield a yellow dye when alum is used as the mordant and an orange-red dye when tin is used instead.

All St. John's Wort plants contain Hypericin and Hyperforin as the main constituents, which together are thought to be responsible for its reported therapeutic effects which may be good for certain people (and bad for others). See Slender St. John's Wort for details of these and other compounds present in the Genus.


  Hypericum humifusum  ⇐ Global Aspect ⇒ Hypericaceae  

Distribution
 family8St John's Wort family8Hypericaceae
 BSBI maps
genus8Hypericum
Hypericum
(St John's-worts)

TRAILING ST. JOHN'S-WORT

Hypericum humifusum

St John's Wort Family [Hypericaceae]