75-85 day maturity. Lactuca sativa var. asparagina ‘Purple Sword Celtuce’. Purple Sword Celtuce Lettuce Seeds. Non-GMO, cool-season annual heirloom. This variety of Chinese stem lettuce has good tolerance to cold and cracking. Chinese stem lettuce originated in southern China and came to the U.S. in the 1800s. It is grown for the stalks and leaves, which can be used as Choi in stir-fries with meats. The leaves are greenish purple, and the stem skin is light purple. Purple Sword is best for spring and fall planting. Approx. 28,400 seeds / oz.