Lettuce leaves are edible.

The height is 25-100 centimeters, the stem is erect, solitary, the basal leaves and lower stem leaves are large, undivided, oblanceolate, elliptic or elliptic-oblanceolate, the tip is acute, short acuminate or rounded, sessile, the leaves in the lower part of the panicle branches and on the panicle branches are extremely small, ovate-cordate, sessile.

Lettuce is taprooted, with most lateral roots occurring after transplanting, shallow and dense, mainly in the 20-30 cm soil layer. The stem is short and contracted. Leaves are alternate, lanceolate or long ovoid, etc., light green, green, dark green or purple-red in color, leaf surface spreading or wrinkled, entire or notched.

Growth habit

Lettuce is a cold-hardy vegetable, preferring cooler climates and not tolerating high temperatures. The germination temperature is above 4℃, 15-20℃ is the best, if the temperature is more than 30℃, it will not germinate. Seedlings can tolerate sub-zero temperatures, the appropriate temperature for seedling growth is 15-20 ℃, the growth temperature of the stem is 11-18 ℃. Lettuce like day and night temperature difference, flowering and fruiting require higher temperatures, the appropriate temperature for 19-22 ℃.