Oxalis (zuo) belongs to Oxalis (eight species in China) of Oxalicaceae. Ordinary oxalis flowers are yellow and originated in China, but the picture provided by the subject should be oxalis rubra, which originated in tropical South America and was introduced as an ornamental plant in China. Now it is mostly wild oxalis in the south, which can be used to treat throat swelling and pain, dermatitis and eczema, snake bites, burns and bruises, and other related diseases, as well as damp heat and menstruation in the body.

Oxalis is widely distributed in the south and north of China, and it seems that they can be seen everywhere. They can grow tenaciously in flower beds, roadside, corner and even their own flowerpots. Although they are unremarkable, they grow in wild forests, and there are many kinds of wild plants with different shapes in these forests. Oxalis is also one of the most common small dwarf grasses in rural areas, but its appearance is very beautiful. Although it looks ordinary like a short weed before flowering, after it blooms,

This kind of sour grass has many uses. In my hometown, it is called acid plant board, and some are sour. As a gardening lawn, it is also called clover. It includes oxalis purpurea, oxalis flavescens, oxalis albiflora and oxalis purpurea. Trifolium repens is very common in urban greening. It is often used as a lawn, with strong expansion and vigorous growth. It needs to be pruned every month all year round. When it blooms, a plate of flowers on its head is like an open umbrella, bloom white, which rotates with the swaying branches under the breeze.

Wild Oxalis is also called "sour", a perennial herb with basal leaves or thin petioles with palmately compound leaves and small leaves like hearts. Its roots are like miniature "white radish", and many rural children like to dig and eat it.