categoryZTrees Trees List 
categoryZBroadleaf Broadleaf List 
categoryZDeciduous Deciduous List 

BASTARD SERVICE-TREE

GERMAN SERVICE-TREE

Sorbus x thuringiaca

Rose Family [Rosaceae]

Flowers:
month8mar month8march month8apr month8april month8may

Berries: berryZpossible      berryZorange berryZred  (astringent, edible when cooked, a pome)
berry8aug berry8sep berry8sept berry8oct berry8nov

category
category8Trees
category
category8Broadleaf
category
category8Deciduous
status
statusZnative
flower
flower8white
 
inner
inner8green
 
morph
morph8actino
 
petals
petalsZ5
 
type
typeZclustered
 
stem
stem8round
 
smell
smell8strong
strong
rarity
rarityZscarce
 
sex
sexZbisexual
 

23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
A shrub or small tree growing to a height of 18m, usually planted, but a rare [RR] when appearing in the wild. It is a species of Whitebeam. Bastard Service-tree grows outwards and upwards (at an angle outwards for branches nearer the periphery) without branches drooping downwards.


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
This specimen early in the year is flowering.


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
The other distinguishing feature for Bastard Service-tree is the shape of the leaves and the way in which they are cut, with the leaflets nearer the stalk being cut deeper, the last one usually cut all the way to the bone, sometimes even with a gap between the others.


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
The leaf at the bottom illustrates the depth of the cut in the leaves increasing as we recede from the leaf tip.


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
The flowers have 5 white petals with numerous longish filaments and small off-white anthers.


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
The numerous anthers well separated and are fanned out over nearly 2π steradians of 3 dimensional space. The centre of the flower is a very pale greenish hue. The sepal cups are green, hairy and with 5 U-shaped cuts creating the sepal teeth.


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
Showing the irregularly cut teeth in the leaf towards the tip. The depth of the teeth decreases towards the leaf stalk as the depth of the cut in the leaves increases, the leaflets at the back having only slight teeth.


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
The obverse of the leaf is minutely hoary hairy.


23rd April 2011, Princes Park, marine lake, Southport. Photo: © RWD
The hairs are appressed to the leaf and still barely visible even in close-up.


16th Aug 2010, Princes Park, marine lake, Southport. Photo: © RWD
The same tree but later in the year, in August when the numerous red berries are ripe.


16th Aug 2010, Princes Park, marine lake, Southport. Photo: © RWD
The berries are in similar isolated small groups just like those of Rowan trees.


16th Aug 2010, Princes Park, marine lake, Southport. Photo: © RWD
Very few berries left on this specimen at head height, having mostly dropped off or been eaten by birds.


16th Aug 2010, Princes Park, marine lake, Southport. Photo: © RWD


16th Aug 2010, Princes Park, marine lake, Southport. Photo: © RWD
A larger clump of berries, which vary in diameter. The remains of the flower are still attached in the dimple at the top.


16th Aug 2010, Princes Park, marine lake, Southport. Photo: © RWD
The multiply-branched nature of the tree, branched almost from ground level upwards.


16th Aug 2010, Princes Park, marine lake, Southport. Photo: © RWD
The bark has horizontal markings.


Not to be semantically confused with : Bastard Balm (Melittis melissophyllum), Bastard Agrimony (Aremonia agrimonioides), Bastard Cabbage (Rapistrum rugosum), Bastard Toadflax (Thesium humifusum) or Tall Ramping-fumitory (Fumaria bastardii) [plants with similar names belonging to differing families]. Bastard Service Tree (aka German Service-tree) is the hybrid of:

  • ??? (Sorbus × pinnatifida) with ??? (Sorbus × semipinnata) which are both hybrids themselves!
    Another source has it that Bastard Service-tree is the diploid hybrid between:
    Rowan (Sorbus aucuparia) and Common Whitebeam (Sorbus aria) which is much simpler, but possibly wrong(?)

Bastard Service-tree is rare native occurring only in several parts of the UK but is also cultivated and planted.

Some similarities to : other Whitebeam trees but less so to Rowan trees (species of Sorbus)

The ripe berry (actually a pome) is only edible when cooked. When raw the pomes are extremely astringent containing ParaSorbic Acid which has a 6-membered ring and is also a lactone - (as well as Sorbic Acid - aka 2,4-HexaDienoic Acid), the former of which causes indigestion if the berries/pomes are eaten and possible kidney damage. When cooked the ParaSorbic Acid is converted to Sorbic Acid rendering them non-toxic.

Simple Acids within Sorbus species


Parasorbic Acid is synthesized within the 'berries' (which are actually pomes) of Bastard Service-Tree (and quite possibly many other Sorbus species) as the precursor to making Sorbic Acid. ParaSorbic Acid is both an astringent and is toxic to consume causing indigestion, nausea and sometimes death.

Sorbic Acid (aka 2,4-HexaDienoic Acid) is a linear molecule and colourless solid which slowly sublimes and is only slightly soluble in water. It too is present in the 'berries' of Bastard Service-tree (but was first found in unripe berries of the Rowan Tree) - and which also need cooking before they are safe to eat for much the same reason. Sorbic Acid or its salts with Sodium, Potassium or Calcium, are used as a preservative in foods and drinks to prevent moulds growing. The salts are more usually used as they are more soluble in water. It is to be found in both cheese and bread.

The berries are edible only when cooked. Cooking converts the Parasorbic Acid to Sorbic Acid (they are nearly isomers of each other - except that Sorbic Acid has one extra hydrogen molecule). Sorbic Acid is a linear molecule and is acidic, whereas ParaSorbic Acid has a 6-membered Pyranone ring and is a lactone.


  Sorbus x thuringiaca  ⇐ Global Aspect ⇒ Rosaceae  

Distribution
 family8Rose family8Rosaceae
 BSBI maps
genus8Sorbus
Sorbus
(Whitebeam)

BASTARD SERVICE-TREE

GERMAN SERVICE-TREE

Sorbus x thuringiaca

Rose Family [Rosaceae]