'What on earth', you may ask, 'is the hybrid bilberry?' To which question most people would be obliged to reply 'I haven't got a clue!' But you dear surfer, now that you have this article before your close scrutiny, have the opportunity to impress your friends and loved-ones with your superior knowledge of the flora of Cannock Chase. Read on!
First identified as a distinct species by a German botanist in 1826, the Hybrid Bilberry was not recognised in Britain until 1870 when it was found living in Maer Woods in north-west Staffordshire, and was first identified on Cannock Chase a few years later in 1886. Now known to occur in several northern European countries, its range in the British Isles is restricted to the upland regions of the English counties of Staffordshire, Derbyshire and Yorkshire, being found in a total of only 25 separate locations. The species is far more prolific on Cannock Chase in Staffordshire than anywhere else, and this has led to it being sometimes called the 'Cannock Chase Berry'.
The Hybrid Bilberry (Vaccinium x intermedium Rultie) is a cross between Common Bilberry (Vaccinium myrtillus) and the Cowberry (V. vitis-idæa), displaying characteristics of both parent species, as its scientific name implies. The natural habitat for all three species is the same, that being open heath or moorland, or open woodland, with a marked preference for acidic soils, the hybrid, however, is able to withstand harsher environmental conditions. The berries of all three plants are edible, being rich in Vitamin C, and can be used in a variety of recipes from preserves to pies. Their leaves and berries also have known medicinal properties, containing arbutin, pectin, and other active ingredients in varying amounts.
| Bilberry | Hybrid | Cowberry | |
|---|---|---|---|
| Leaf Habit | deciduous, falling every Autumn | evergreen, lasting 2 or 3 years | evergreen, lasting 4 to 5 years |
| Leaf Shape | thin and somewhat wrinkled, with a pointed tip | thicker than bilberry, less wrinkled, with a blunt tip | somewhat fleshy, with an indentation at the tip |
| Leaf Colour | same light green colour above and below | semi-glossy light green above, paler beneath | glossy dark-green above, lighter matt-green below |
| Stems | sharply angled | generally rounded with some degree of ridging towards the top | rounded |
| Flowers | dark reddish-pink, borne singly | pale pink, borne in small bunches of between 2 to 8 | pinkish-white, borne in bunches of 6 to 12 |
| Fruit | rounded blue-black, sweet-tasting berries, 6-8mm in diameter | blue-black berries closely similar to bilberry, which although somewhat larger, are noticably less abundant | globular red berries, 0.8 - 1.2 cm in diameter, somewhat acidic |
The Hybrid does not occur where either of the the parent plants are absent, and the precise method of propagation is not known. Experiments in hybridization using both the parent plants and the hybrid itself, have repeatedly failed to reproduce the species. The reason why the hybrid appears only in specific locales, and does not occur everywhere that both parent species habituate is currently unknown, as are the causes of its proliferation on Cannock Chase.