Of more than a hundred named varieties of cranberries, four varieties account for 85 percent of the harvest. All four were discovered in the wild before 1900 .
These four are Howes from Basset Swamp, East Dennis, Mass., Early Black from a swamp in Harwick; McFarlin' from New Meadows bog in South Carver, Mass. and Searles from a swampy brush patch in Walker, Wisconsin.
In all, this adds up to about 25,000 acres of cranberries, and although there seems little likelihood that the United States will ever increase its cranberry acreage dramatically, the situation is different in Canada.
For centuries cranberries were picked by hand scoops. Today scoops are sometimes used at the edges of bogs, but more are used as magazine racks and flower planters.
The two methods used today are dry and wet harvesting. Dry harvesting is done with a mechanical picker called a Darlington machine. It is used when the berries are to be sold fresh, for they are unbruised. But the machine can miss as much as 20 to 30 percent of the fruit, if the bag isn't level.
Because of this most cranberries are now wet harvested. The bogs are flooded and since cranberries have an inside air space, they float.
Partly as a result of switching over to wet harvesting, which not only results in more fruit but is less punishing to the vines, the yields of cranberries have been increasing. The average harvest is 100 barrels per acre, but some growers consistently harvest 250 to 300 barrels per acre.