Yesterday I mentioned how each year different plants tend to predominate along roadsides and fence rows. This year the common sunflowers are prolific. The other plant growing in profusion is prickly lettuce (Lactuca serriola). Conditions must be perfect for sunflowers since prickly lettuce is also a member of the sunflower family.
Also commonly called wild lettuce or China/Chinese lettuce, prickly lettuce is a relative of garden lettuce and will sometimes hybridize with cultivated lettuce. A European native, this biennial or winter annual is now naturalized throughout most of North America.
Reproducing only by seeds, prickly lettuce has a single stem that branches only in the flowering portion. The alternate leaves are pinnately lobed or can be lobeless. The leaves clasp the stem with two earlike flaps and oddly, twist so that the upper leaf surface faces the ground. There are prominent, sharp spines on the leaf margins and on the backsides of the midribs. A sticky white latex (milk) is found in the leaves and stems of prickly lettuce. The delicate yellow flower heads are composed only of ray flowers. The fruits are flattened and have bristles (pappus) at the top end.
Prickly lettuce is a serious invader in disturbed soils, irrigated crop lands and orchards – a noxious weed! It is also common along roadsides, gardens and yards.
The young leaves are edible if picked before the spines stiffen and they are filled with the bitter latex. The mature plant is definitely unpalatable. I personally prefer to not bother attempting to eat prickly lettuce because the window of palatability is so narrow.
Prickly lettuce is also known as lettuce opium because its milky latex has weak narcotic properties. Herbalists consider prickly lettuce a safe and mild sleep aid and painkiller. To harvest the latex, minute amounts must be scraped from the thin stems and then dried, a long and tedious process. For an individual to get any quantity sufficient for medicinal use or recreational activity is unrealistic.
These prickly lettuce plants were along the road in front of our property (Modoc County CA).