Flower:

Branching cluster of stalkless flowers with usually a single flower, sometimes 2, in the axils of leaf-like bracts. Flowers are cup-shaped, tiny, less than 1/16 inch across, lacking petals but with 5 petal-like sepals that have a green to brownish midvein and whitish edging. In the center are 5 stamens and 2 short styles. At least some flowers may not open but remain closed and bud-like. Bracts are oval-elliptic, pointed or blunt at the tip, and hairless.

Leaves and stems:

Leaves are opposite, erect to ascending, mostly oval-elliptic and widest near the middle, 1/8 to 1 inch long, up to 3/8 inch wide, toothless, hairless, pointed or blunt at the tip, and narrowed to a short stalk-like base. At the base of a leaf is a pair of papery, narrowly triangular to awl-shaped appendages (stipules) up to about 1/8 inch long.

Stems are erect, smooth, very slender, green to reddish, and much branched with spreading, forked branches, the stem swollen at branch and leaf nodes.

Fruit:

Fruit is a round to oval capsule, longer than the persistent sepals, and matures from green to reddish-brown. Inside is a single seed.

Notes:

At first glance, Smooth Forked Nailwort may look like just another Chickweed, but it is actually quite rare in Minnesota, where it reaches the northern fringe of its range. According to the DNR, there are only 5 known locations, one of which has not been relocated since 1920 (likely now extinct). It was listed as a Threatened species in 1996 and elevated to Endangered in 2013, after biological surveys in the southeast counties failed to locate any new populations; it is currently listed as Special Concern in Wisconsin. A species of dry, sandy savanna usually associated with oaks or Jack pine, threats are the usual: habitat destruction from development, agriculture and invasive species. It is distinguished from similar species by the tiny flowers (1/16 inch or less), numerous forked branches, swollen branch nodes and narrow stipules at the leaf base.