MEDLAR TREE AND MEDLAR FRUIT, MESPILUS GERMANICA
The medlar is a member of the rose, Rosaceae family and until 1990 was thought to be the only medlar tree in existence. However, a wild variety of medlar, Mespilus canescens was found in Arkansas in the US. However, this is “critically imperiled” or “at high risk of extinction due to extreme rarity” according to the IUCN Red List. These medlars are close relatives of the hawthorn and pear, and are also related to loquats, apricots, plums, peaches, Alpine Lady’s Mantle, Lady’s Mantle, parsley-piert, avens, cinquefoil, silverweed, apples, dog roses and blackthorn, to name but a few of its relatives. 
Eating a medlar is not usually a question of eating it straight from the tree as it has to be bletted, which means that it has to begin to decay before it is palatable. If there has been a frost then this bletting can occur naturally and some people let their medlars blet on the tree. However they can be harvested while still green and then laid in a bed of sawdust or bran in a cool dark place, to decay. The brown flesh can then be scooped out and eaten, or cooked. The seeds contain hydrocyanic acid, however, and so must not be eaten. There is a recipe on this site for medlar jelly, which goes well with pheasant. The pulp is a mild laxative, so you shouldn’t eat too much of this fruit. 
It is believed that medlar trees are indigenous to south west Asia and possibly also to south east Europe. They grew along the Black Sea coast in Bulgaria and Turkey, and were known to the ancient Greeks and Romans, who had them in the second century BC. They were popular in the Middle Ages but fell out of favour when other fruits were introduced.
Medlars look a little like a crab apple crossed with a rosehip, and were very popular with the Victorians. They stewed them and ate them with cream, and a dessert was made with them as you would make lemon curd. 
The medlar bark was once used, although not very successfully, as a quinine substitute. The fruit, leaves and bark have all been used in medicine. Nicholas Culpeper, the English herbalist, writing his Herball in the 17th century has this to say about them:-“Government and virtues. The fruit is old Saturn's, and sure a better medicine he hardly hath to strengthen the retentive faculty; therefore it stays women's longings. The good old man cannot endure women's minds should run a gadding. Also a plaister made of the fruit dried before they are rotten, and other convenient things, and applied to the reins of the back, stops miscarriage in women with child. They are powerful to stay any fluxes of blood or humours in men or women; the leaves also have this quality. The decoction of them is good to gargle and wash the mouth, throat and teeth, when there is any defluxions of blood to stay it, or of humours, which causes the pains and swellings. It is a good bath for women, that have their courses flow too abundant: or for the piles when they bleed too much. If a poultice or plaister be made with dried medlars, beaten and mixed with the juice of red roses, whereunto a few cloves and nutmegs may be added, and a little red coral also, and applied to the stomach that is given to casting or loathing of meat, it effectually helps. The dried leaves in powder strewed on fresh bleeding wounds restrains the blood, and heals up the wound quickly. The medlar-stones made into powder, and drank in wine, wherein some Parsley-roots have lain infused all night, or a little boiled, do break the stone in the kidneys, helping to expel it.” The medlar is also mentioned in European literature, with Cervantes referring to them in “Don Quixote”; the eponymous hero and Sancho Panza “stretch themselves out in a field and stuff themselves with acorns or medlars.” 
Shakespeare also mentions the medlar disparagingly in his plays, notably in “Romeo and Juliet” Act 2 scene i, when Mercutio laughs at Romeo’s unrequited love for Rosaline :- Now will he sit under a medlar tree
And wish his mistress were that kind of fruit
As maids call medlars, when they laugh alone.
O Romeo, that she were, O that she were
An open-arse and though a poperin pear.”
(“Open-arse “was a common name for the medlar fruit because of the way the top of it looks.)
Again he mentions the medlar in “Measure for Measure” Act 4 scene iii, when Lucio excuses his denial of his past sexual exploits, saying, “they would else have married me to the rotten medlar.”
Geoffrey Chaucer also mentions the medlar in the “Prologue to the Reeve’s Tale”
“This white top advertises my old years,
Mt heart, too, is as mouldy as my hairs,
Unless I fare like medlar, all perverse,
For that fruit’s never ripe until it’s worse,
And falls among the refuse or in straw,
We ancient men, I fear, obey this law,
Until we’re rotten we cannot be ripe.”
John Gerard, writing in the 16th century clearly enjoyed eating medlars as he wrote, that they were “often perfumed with sugar or honey and so being prepared are pleasant and delightfull.” This is doubtless because of the smell of the fruit which can be off-putting as it is musty. However when cooked it loses some of this smell.
