There is many different various of lettuce seeds at China,but compare to American ,there is more.Why?Because of lettuce is good for salad,and American like it very much . 【 Lettuce 】 What we see mostly at supermarket is ： Romaine (Cos) 、 Iceburg (Crisphead) 、 Butterhead (Boston/Bibb/Limestone) 、 Green Leaf (Coral) 、 Red Leaf (Red Coral) 、 Green Oakleaf 、 Red Oakleaf 、 Arugula 、 Stem 、 A Choy 。 Romaine(cos)lettuce,that most popular varity at American market. Iceburg(Crisphead),taste very crisp,Usually see at hamburger. butterhead,like butter,so smooth and good looking! Green leaf lettuce and Red leaf lettuce,litter bitter,different color. Green oak  and Red oak,also popular at salad dinner! At China,it aslo called roquette seeds Stem lettuce ,it aslo called celtuce lettuce ,big stem ,some round leaf,some sharp leaf,Mostly are resisant to cold,only part are resisant to heat,Some stem are red too.It usually eat it it stem,can be fry or pick