I found this information online to be very interesting. There are no pictures to copy so I had to make my own drawings.
Short season potatoes are called Determinate Potatoes. After the plants grow about 30 days how every tall they are is where all the potatoes will grow to the plant stem. If you cover your seed potato with 6" of soil and it takes 30 days for the tops to make there way through the soil to sunlight all the potatoes the plants will produce will be below the soil surface. Covering plants & potatoes with more soil after 30 days does not produce more potatoes it only keeps new potatoes out of sunlight.
Long season potatoes are called Indeterminate Potatoes. How ever tall plants are after 30 days has nothing to do with how many potatoes the plant will produce. Plants have the ability to grow potatoes the full length of the plant stem that is covered with soil up to a certain number of days about 65 to 70 days. Keep covering the plants with more soil as they grow to keep sunlight off new potatoes. If you don't cover your plants with more soil they will produce less potatoes. Long season potatoes grow well in hot weather climates.
When plants blossom new potatoes are starting to grow under the soil. When plants above the soil start turning yellow and die plants are finished growing potatoes but do not dig potatoes up yet. Skins are very tender on new potatoes so leave them in the soil until most of the plant is dead about 3 weeks to toughen the skins.
Online says, long season potatoes can produce a crop 2 or more times larger than short season potatoes. It also says, some short season potatoes are large producers that can almost equal a long season potato crop.
Online lists a long list of about 40 or so short season potatoes & about 50 or so long season potatoes that I have never heard of. No pictures, no information, if your interested I guess you need to look them up. The rest of the world had potatoes long before the USA. Andes Mountains has over 125 different varieties of potatoes growing at every elevation up to 12,000. feet.