=Yam= (_Dioscorea alata_). Yams, the tubers of various species of _Dioscorea_, are cultivated in nearly all tropical countries. Yam tubers abound in farinaceous matter and often reach a large size. They resemble but are inferior to the sweet potato.
Time given is for latitude of New York. Each one hundred miles north or south will make a difference of from five to seven days in the season. The distances given here indicate the distance apart the plants should stand after thinning. The seed should be sown much nearer together. CLASS A. These plants may be started early (in the greenhouse or hotbed, in early spring, or outdoors in the seedbed later), and afterwards transplanted to their permanent location. CLASS B. These crops usually occupy the ground for the entire season. CLASS C. These are quick maturing crops which, for a constant supply, should be planted at several different times in “succession”--a week or two weeks apart. CLASS D. These are crops which often may be cleared off in time to permit planting another quickly maturing crop, usually of some early variety. CLASS E. These crops are supplementary to those in Class D and may be used to obtain a second crop out of the ground from which early crops have been cleared.