Bramble or blackberry
Leaves and Stem
The bramble forms an underground, perennial rootstock that throws up new shoots in the Spring. These are have a two-year ‘life span’, i.e. they are biennial. In the first year, growth is vigorous and vegetative. If the tip of the shoot meets the soil then it may develop roots and form a daughter plant. This is a form of vegetative or asexual reproduction; plants formed in this way will have the same genetic make up as the parent plant.
The leaves on these first year shoots are compound and palmate (that is like an open hand) - with 5 – 7 leaflets. In the second year, lateral shoots develop which bear the flowers. The leaves on these lateral shoots are somewhat smaller. They often have 3 – 5 leaflets. The leaves have been used in various herbal remedies.
Flowers and Fruits
The flowers form in late spring / early summer and are white or pale pink, and have five petals and numerous stamens. The fruit, the blackberry, develops from these flowers.
The fruit of the bramble is the blackberry, but in a strict botanical sense,the blackberry is not a berry. Each tiny juicy ‘blob’ on the blackberry represents a tiny fruit or drupelet, and there are many of them so it is an aggregate fruit . A drupe is a fruit that has a fleshy, outer part that surrounds a stone or seed. So, a drupelet is a tiny drupe.
Some brambles produce fruit and seed without fertilisation – though the transfer of pollen to the stigmas of the flowers may be required to stimulate fruit and seed formation.
This form of reproduction (which is neither truly asexual or sexual) is known as apomixis*. Brambles and dandelions both make use of this method. Some brambles are also polyploid, that is, their chromosome number has doubled or trebled.
Ecology and other notes
The bramble is a common native species. It is found in many different types of plant communities from woodlands, to hedgerows, heaths and dunes. It is not found in native pine woodland, and is generally more common in lowland than upland woods.
Blackberries have formed part of the human diet in Western Europe for thousands of years. Examination of ‘Haraldskaer woman’ indicated the blackberries formed part of her diet. Apart from us as a species, the bramble is a significant source of food for many insects and mites, with some species feeding exclusively on bramble. It is also important to dormice, who eat their flowers and fruit. They, and other animals / birds, seek refuge in bramble thickets. The leaves also represent a food source for deer, whose browsing may affect the development of bramble thicket.
High numbers of deer can result in a reduction in the amount of bramble and consequently, the amount of wildlife in a given area. Large amounts of bramble can affect the microclimate of the ground / herb layer; influencing the growth and development of other plants. On one hand, it can offer protection from grazing / browsing to young tree seedlings but equally it can suppress the development of light loving species.
As a result of apomixis*, polyploidy and crossing, many microspecies of bramble have formed. These are quite difficult to identify, relying on minute differences in the flowering and non-flowering shoots, the leaves, the prickles and young fruits. Because of these many micro-species, the bramble is considered to be an aggregate species – and is written as Rubus fruticosus agg.