Pyrus cordata
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P. cordata
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| Pyrus cordata |
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Pyrus cordata, the Plymouth pear,[2] is a wild species of pear belonging to the Rosaceae family.
It is a small tree, often found growing in hedgerows or at the edge of woods. The Plymouth pear is considered to be either a sub-species of Pyrus pyraster (European Wild Pear) or a distinct species.[citation needed]
Contents
Description
Pyrus cordata is a deciduous shrub or small tree growing up to 10 metres in height. It is hardy to zone 8[clarification needed] and is not frost tender, but its ability to bear fruit and thus seed is dependent upon favourable weather conditions. It is in flower from April to May. The flowers are hermaphrodite and are pollinated by Insects. The trees have pale cream blossom with some pink. The smell of the blossom has however been described as a faint but disgusting smell compared to rotting scampi, soiled sheets or wet carpets. The odour attracts mainly flies including some more often drawn to decaying plant matter such as Bibio marci.
Pyrus cordata prefers light (sandy), medium (loamy) and heavy (clay) soils, requires well-drained soil and can grow in heavy clay soil. It prefers acid, neutral and alkaline soils. It can grow in semi-shade (light woodland) but prefers full sun and often grows in hedgerows and at the edges of woodlands. It requires moist soil and can tolerate drought. It can also tolerate atmospheric pollution. It is common in Brittany, Northern Portugal and Galicia where it occurs at woodland margins on acid soils.
Distribution
The Plymouth pear has an Atlantic distribution and is found in Western Europe in France (notably in Brittany), Portugal and Galicia and with a small presence in the United Kingdom (in England and Cornwall) where it is now believed to be an archaeophyte.
Habitat
It occurs in thickets and open woods with cool-temperate climates, in lowlands and hills. Not much about its requirements in the UK are known, but conservationists are looking at how it behaves in Brittany to get an idea about its requirements.
English & Cornish population
The species receives its English name from the area it was originally found growing in; Plymouth in 1871 by a local naturalist; T. R. Archer Briggs. In the United Kingdom the species is very rare and is confined to two areas – Plymouth and Truro.
The genetic diversity of the species in the UK is very low with the two widely scattered populations being genetically identical which suggests that one of the populations was established from clone material taken from the other (suckers or cuttings).
However this lack of genetic diversity is a threat to the population because most of the seeds are infertile, but efforts are being made to conserve the population by controlled breeding of trees in botanical gardens and by attempting to induce genetic mutations and variation in cultivated specimens. Genetic material from other parts of Europe is being avoided, so no trees are being introduced from the mainland European population. The conservation of the species involves attempting to increase the genetic diversity and so it is hoped that some mutations will take place with the cultivated stock which it is hoped will allow them to breed more successfully (Pears are self-sterile, so clones cannot breed easily with other clones).
The species suffers from low seed fertility caused by the inbreeding of the two, British populations and conservation efforts are attempting to combat this. The two populations are also threatened by the use of the landscape but they are being preserved in protected areas in their range.
Botanists at Kew Gardens where conservation efforts are taking place have concluded that the Plymouth Pear was brought from Brittany as a hedging plant several hundred years ago.
Notes
References
- Edward Milner – Trees of Britain and Ireland, page 115
- Jackson, 1995
- Pyrus cordata at Arkive
- Kew Gardens page about Pyrus cordata
- Pyrus cordata datasheet (PDF)
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