there are a number of theories about that:

There are a number of theories to explain this discrepancy:

   * It was an early marketing attempt, something like the naming of Greenland by Erik the Red. In this theory, Leifr's naming of Markland and Vinland was to encourage others to explore and settle there.

   * A theory subject to much debate among scholars is that there was a misinterpretation of short-i *Vinland as long-i Vínland. In this theory the naming is based on the Old Norse word (short-i) vin f meaning 'meadow; pasture'. Vin is a common name on old farms from Norse times in Norway, and present-day use of the word are Bjørgvin, the Norse (and Icelandic) name of Bergen, Norway, and Granvin, where vin translates into 'pasture' in both. A poetic Norse name of the Danish island of Sjælland (Zealand) was Viney 'pasture island'. The actual word also existed in Old English, and an interesting parallel to the Norse name Vinland is the name of the village Woolland in Dorset: This was written "Winlande" in 1086, and it is interpretted as 'meadow land'. This theory can be combined with the previous one: Estridson might have embellished Adam's mistake if he believed it would increase the fame of Vinland for joint financed ventures he would no doubt claim for himself. One problem with this theory is why the sagas outside of Adam of Bremen's account also refer to long-i Vínland, and mention vines as well. Since the sagas were written later, an explanation for this could be that the sagas were somehow influenced by Adam of Bremen's account.

   * Alternatively Estridson was joking or lying, or even referring to similarly sounding Wendland instead in an earlier account, where grapes did grow, and this was later confused with Vinland by Adam of Bremen.

   * Another theory is that we have not discovered the true location of Vinland yet, and it is further south, where grapes do grow. More subtly Vinland could be seen as a gateway or northern part, in reach of more temperate areas where grapes grew.

   * Another possibility is that later, longer voyages further south, reporting Concord style grapes confused the story told about the settlement, as there were individuals of the crews who had ventured out on their own to return with tales.

   * Still another possibility is that the reference is to any of the abundant berries in Newfoundland, including gooseberries or blueberries, which are both abundant near L'Anse-aux-Meadows and are both suitable for winemaking.

   * Finally it has been speculated that grapes did in fact grow in Newfoundland (47-51°N) in the past, but not any more due to climatic changes. The time period of the Vinland settlement corresponds with the Medieval Warm Period (from about the 10th century to about the 14th century). Water temperatures in the northern hemisphere during this time were up to 1°C warmer, allowing the planting of vineyards as far north as the coastal zones of the Baltic Sea (ca. 56°N) and southern England (ca. 51°N).