categoryZShrubs Shrub List 
categoryZBroadleaf Broadleaf List 
categoryZDeciduous Deciduous List 

PURGING BUCKTHORN

BUCKTHORN

Rhamnus cathartica

Buckthorn Family [Rhamnaceae]

month8may month8jun month8june

Berries: berryZpossible        berryZgreen berryZblack  (poisonous, purging!)
berry8Aug berry8Sep berry8Sept berry8Oct

category
category8Shrubs
category
category8Broadleaf
category
category8Deciduous
status
statusZnative
flower
flower8green
inner
inner8cream
morph
morph8actino
petals
petalsZ4
type
typeZclustered
stem
stem8round
toxicity
toxicityZlowish
sex
sexZdioecious

18th Aug 2018, private estate, Burscough, Lancs. Photo: © RWD
A deciduous spiny shrub growing up to 8m in height.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
The leaves vary in size from 4 to 9cm and are usually a dark green.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
New growth atop is greener than the older leaves below.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
Many leaves opposite each other, and at alternate angles up the stem. Not all leaves are opposite though - look near the bottom.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
Not all leaves are opposite.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
Normally the flowers are more numerous than this. They have flower stalks which are between 6 to 25mm long with a narrowly-cupped sepal tube with usually 4 green sepals and 4 petals - the latter are free.

 Purging Buckthorn is Dioecious, having separate male and female plants. The one at Moore here has anthers in the flower (centre left) and therefore must be a male plant and therefore this particular shrub will not bear the blackish berries. There are normally 4 anthers. The flower stalks emerge from near the top of a sheath around the stem. The flowers in this photo are well past their best.



5th Sept 2018, Martin Down, Dorset. Photo: © Jill Stevens
After flowering the poisonous black fruit appear.


25th Aug 2017, Martin Down, Dorset. Photo: © Jill Stevens
The berries are almost black and in groups close to the stems.


25th Aug 2017, Martin Down, Dorset. Photo: © Jill Stevens
Even their stalks and discoidal attachment are black.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
The leaves have between 2 to 4 main pairs of curved lateral veins, sometimes up to 5 pairs.


18th Aug 2018, private estate, Burscough, Lancs. Photo: © RWD
New branch buds are forming in the leaf-stem axils.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
New branch buds forming in leaf-stem axils. The stem is expanding in girth stretching the greyish papery bark leaving gaps.


18th Aug 2018, private estate, Burscough, Lancs. Photo: © RWD
Younger or leaves not in full sun could be paler green.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
Upper surface a darker green than under-surface (see below). Veins indistinct from upper surface.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
Under surface a paler green than upper surface (see above). Veins prominent on underside of leaves and the much smaller connecting veins can also be seen as a fine darker-green interconnecting network.


1st Sept 2018, Moore Nature Reserve, Warrington, Lancs. Photo: © RWD
Smaller veins numerous between main veins. The leaf teeth are numerous, tiny and blunt.


18th Aug 2018, private estate, Burscough, Lancs. Photo: © RWD
The bark with an interloping leaf on the left.


18th Aug 2018, private estate, Burscough, Lancs. Photo: © RWD
Unlike Alder Buckthorn there are spines on the shrub, but they are not all that numerous and hard to spot on their thin twigs. Not as harmful as those on Blackthorn or Sea-Buckthorn!


Easily confused with : Flower () [plants with similar names belonging to differing families]

Not to be semantically confused with : Fairy Flax (Linum catharticum), Rescue Brome (Ceratochloa cathartica), nor with species of Buckeye such as Yellow Buckeye (Aesculus flava) nor with Buck's-Beard (Aruncus dioicus), Buckwheat (Fagopyrum esculentum) or Buck's-horn Plantain (Plantago coronopus) [differing species belonging to widely differing families with similar names]

Can be confused with : Other Buckthorns, some of which belong in a different Genus, Frangula, but both genera belong in the same Family Rhamnaceae:

PURGING BUCKTHORN
Rhamnus
cathartica
MEDITERRANEAN BUCKTHORN
Rhamnus
alaternus
ALDER BUCKTHORN
Frangula
alnus
Type Deciduous Evergreen Deciduous
Spines with spines no spines no spines
Leaf Teeth teeth present, many, fine fewer, widely spaced, none near stalk teeth absent
Leaf Veins 2-4 (max 5) pairs 3-6 pairs 6-10 pairs
Leaf Size 4-9cm 1-6cm 2-7cm
Fruit Size 6-10mm, ~globose 4-6, obovoid 6-10mm, obovoid
Fruit Seeds 3-4 seeds 2-3 seeds 2-3 seeds
Flower Stalk 6-25mm 3-10mm 8-14mm
Petals 4 0 5
Sepals 4 5 5
Anthers 4 5 5

No relation to : Sea-Buckthorn (Hippophae rhamnoides) a spiny shrub found near the sea with bright orange berries [a plant with similar name belonging to a differing family].

If the berries are consumed, they are mildly toxic, causing almost immediate violent stomach cramps, regurgitation and a laxative effect. It is said that both an Aglycone AnthraQuinone (without any glucosides) and Emodin in the berries are responsible for these symptoms. Emodin acts as an anti-microbial protecting the fruit from bacterial and fungal attack. The concentration of emodin diminishes as the fruit ripens. The specific epithet cathartica eludes to these properties. It could be that the mild toxins dissuade birds from eating the unripe berries, but allow them to eat ripe berries without too much trouble. Buckthorn is distributed by birds after consuming the fruit and subsequently excreting the seeds undigested.

It is found especially on lime soils in scrub, hedges, woods and fens but also on peat soils. It is native.


  Rhamnus cathartica  ⇐ Global Aspect ⇒ Rhamnaceae  

Distribution
 family8Buckthorn family8Rhamnaceae

 BSBI maps
genus8Rhamnus
Rhamnus
(Buckthorns)

PURGING BUCKTHORN

BUCKTHORN

Rhamnus cathartica

Buckthorn Family [Rhamnaceae]