The "black truffle" or "black Périgord truffle" "Tuber melanosporum" is named after the Périgord region in France and grows only with oak. Specimens can be found in late autumn and winter, reaching 7 cm in diameter and weighing up to 100 g. Production is almost exclusively European, with France accounting for 45%, Spain 35%, Italy 20%, and small amounts from Slovenia, Croatia and the Australian states of Tasmania and Western Australia (see below). In 1900, France produced around 1,000 metric tonnes (1,100 short tons) of "Tuber melanosporum". Production has considerably shrunk in the past century, and is now around 20 metric tonnes (22 short tons) per year, with peaks at 46 metric tonnes (50 short tons) in the best years. About 80% of the French production comes from southeast France. The largest truffle market in France (and probably also in the world) is at Richerenches in Vaucluse. The largest truffle market in southwest France is at Lalbenque in Quercy. These markets are busiest in the month of January, when the black truffles have their highest perfume. As of December 2009, black truffles were sold for about €1,000 per kilo in a farmer's market and €3,940 per kilo in a retail saler.