I live in northern part of Alabama. The lemons turn yellow and have a very strong smell just before fall or mid September.

This is a difficult one to answer because horticulturalists (the people who work with plants and agricultural crops) are always experimenting with new varieties and cultivars of lemons, thus increasing the possible number of types.

There are also difficulties in determining exactly what counts as a “lemon type”. For example, Meyer lemons are thought to be a cross between a lemon and a mandarin orange, but can we count this a lemon type even though it is not a ‘true’ lemon? If we do count it, then we need to look at all of the other hybrid varieties and count those too, but it is hard to pin down an exact number on this because there are always new developments. On the other hand, if we don’t count hybrids and only consider true lemons, we will need to trace their lineage and be sure that they are really true lemons and have not been crossed with something else at some point in their history.

For something like a school assignment, I would probably give an answer of “10 to 20, depending on exact classification”. If forced to give an exact number, I would just say 10 (this is the number of varieties listed at Wikipedia). Most sites list five to ten major types. I have not yet been able to find an authoritative source that provides an exact number.

@Robin:

I did some research on this one but have not yet encountered any “official” lemon type that is uniformly used for lemonade at all state fairs. I suspect that each state fair uses whatever lemons are available to them for a relatively low cost.

Distinctive green and yellow variegated foliage. Lemons have pink flesh, clear juice, and acidic lemon flavor. Fuchsia colored new growth and flower buds. Excellent landscape tree prized more for interesting variegated foliage than for fruit quality and quantity.

I would interpret “acidic lemon flavor” to mean that the fruit is probably a little on the tart side. Of course, when we’re talking about lemons, these things are relative — to my tastes, ALL lemons are basically tart compared with just about any other food or drink! If you want something sweeter than the natural taste of the fruit, you can always add some sugar to it after harvesting, or use the juice to make lemonade (or pink lemonade in the case of this pink variegated variety).