Phyllanthus caroliniensis , whose common name is Carolina Leaf-flower, is a native plant, a warm season annual that spreads rapidly and is considered a broadleaf weed. It characteristically likes wet areas like roadside ditches and low areas of lawn. Carolina Leaf-flower has a traditional, uniform leaf and branching form, as shown in the photo below of a mature plant. The leaves are widely spaced on the stems, so the plants never have a dense appearance.
This plant is often hard to recognize, because it rarely stands alone, as in the above shot. More often it is part of a cluster of weeds and grasses and is difficult to separate visually from the foliage, as seen below.
The following is a closer view of the stem and leaf patterns.
Both of North Carolina’s Leaf-flowers are incredibly persistent. This is partly due to the fact that they flower and produce fruit continuously from May into November. The flowers are located at the leaf axils and are very tiny, as illustrated below.
Phyllanthus urinaria , a species introduced from Asia, is the second North Carolina Leaf-flower. Its common name is Chamberbitter or Stonebreaker, due to its use as an herbal medication for urinary tract stones. Its effectiveness as an herbal medication could be debated, but its classification as an extremely difficult WEED is unquestioned among gardeners. It is a fast grower, is very drought tolerant, and it flowers and produces large quantities of fruit in just 2 weeks. It is a warm season weed and does not usually germinate until May, which at least gives gardeners a break in the early spring. The stems are tough, so the plant is relatively easy to pull out of the soil intact, but the root system hangs onto a large clot of soil when it is pulled.
The typical plant form is shown below. It is commonly confused with Wild Sensitive Plant (Chamaecrista nictitans) and seedling Mimosa Trees (Albizzia julibrissin)
Its feathery, fine-leaved appearance makes it easier to see on the ground. Also, it prefers the rich soils of gardens and greenway shoulders, where competition with weeds is reduced.
A comparison of the plant form of both species is shown below. On the left is Phyllanthus urinaria and on the right is Phyllanthus caroliniensis. The leaves of P. urinaria are longer and more densely arrayed on the stems; the leaves of P. caroliniensis are ovoid and loosely arrayed on the stems.
A closer comparison of the leaves follows:
Leaf-flowers were formerly placed in the Spurge Family (Euphorbiaceae) but now have been given their own family – Phyllanthaceae. In spite of the appearance, the stem and leaves are not compound leaves with leaflets; what appear to be small leaflets are actually true leaves. As a general rule, compound leaflets will not have flowers at the base. Thus the common name “Leaf-flower” refers to the flowers at the base of true leaves. Also, after the flower blooms, the retained calyx of the fruit looks a lot like a leaf, which contributes to the Leaf-flower name.