As the name suggests the tomatillo is related to the tomato. They are both in the family Solanaceae, also known as nightshades. This plant family gets a bad rap sometimes, and yes, some members are poisonous. But it is a big family and includes many edibles like potatoes, eggplant, chili peppers, and bell peppers.
I have already discussed the tomato and how it is easy to grow. The Tomatillo, also called The Mexican Husk Tomato, is just as easy to grow. I started both the tomatoes and tomatillos this year from seeds in the green house together. I transplanted them to the ground at the same time. They have grown next to each other in the garden and they are now bearing fruit at the same time. They sound like they have a lot in common but that is where the similarities end.
The adult stems and leaves look different from a tomato and the fruit looks totally different. The name Husk Tomato comes from the appearance of the fruit upon ripening. The fruit is like a green (sometimes purple) tomato inside a dry husk like wrapper. When ripe, the fruit will pop out of the husk. The only way I would think these are related plants is that the ripe tomatillo does kind of resemble a unripe green tomato in shape and color.
The husk is not used and can be easily removed and discarded. The tomatillo inside is firmer inside and does not have the tough skin on the tomato. This actually makes canning these easier since they do not need to be blanched and skinned.