Flower:

Flowers are ¼ to 3/8 inch across with 5 oblong petals, slightly notched at the tip, white to pink lavender with darker lines radiating from the base. The 5 sepals are lance-elliptic, hairy on the outer surface with a conspicuous sharp awn at the tip; including the awn, sepals are longer than the petals. Borne in pairs, each flower has a short stalk (pedicel) that splits off from a single short stalk (peduncle) in the upper leaf axils. These stalks are only apparent in a few early blossoms but as the season progresses the flowers are concentrated in the leafy tips with the stalks so short as to appear to be a flat cluster of several stalkless flowers or fruits. New flowers develop continuously through the growing season becoming cleistogamous (without petals, producing seed asexually) in late summer. Sepals and stalks are both hairy with a mix of glandular and non-glandular hairs.

Leaves and stems:

Leaves can be alternate but mostly opposite and simple, the blade kidney shaped to nearly round in outline, up to 3 inches across, hairy on both surfaces and along the edges, deeply cleft into 3 to 9 (typically 5) palmate lobes with coarse, oblong teeth or secondary lobes with rounded or blunt tips. Leaf stalks are up to 3 inches long on lower leaves becoming nearly stalkless in the dense leafy clusters at branch tips. At the base of the leaf stalk is a pair of lance to awl-shaped leafy appendages (stipules). Stalks and stems are green or tinged red and covered in fine grayish hairs, some glandular. Stems are erect to spreading and much branched.

Fruit:

Fruit is an erect capsule-like structure with the persistent sepals around the base. In the center is a slender beak divided into 5 sections, at the base of each is a large oval shaped carpel containing a single seed. At maturity, the sections split apart from the base, flinging the seeds a distance from the mother plant.

Notes:

Carolina Cranesbill can turn a brilliant red at maturity, especially the fruits but the leaves can turn as well. Minnesota has three small flowered Geranium species with deeply lobed, palmate leaves that can be difficult to distinguish at first glance. Native Carolina Cranesbill can be distinguished from the others primarily by its 2 nearly stalkless flowers per leaf axil, crowding at the end of a branch and later appearing as a flat cluster. The non-native Siberian Cranesbill (Geranium sibiricum) almost always has single, long-stalked flowers per leaf axil and its leaf lobes are broadly elliptic and sharply pointed, where the lobes of G. carolinianum are narrower and more fan-like with blunt or rounded tips. The native Bicknell's Cranesbill (G. bicknellii) also has 2 flowers per stalk but they are more spread out along the upper branch axils and are always long stalked. Distribution range can also be a good indicator. With only a few exceptions, in Minnesota G. carolinianum is almost exclusively found in the western and southern prairie regions, especially in and around rock outcrops along the Minnesota River valley. G. bicknellii is predominantly found in northern boreal forests where it responds to disturbances in forest openings, including lumbering and fire.