Perennial herb 30 - 70 cm tall Stem: erect, unbranched below inflorescence. Leaves: few, mostly basal, these long-stalked, large (up to 18 cm wide), deeply palmately five- to seven-lobed, with lobes narrowed at base and large teeth or further lobes near tips. Along the stem there is only a single pair (sometimes two pairs) of short-stalked leaves just below the inflorescence, and these leaves are similar in shape to the basal leaves, but smaller (5 - 1 5 cm wide). Inflorescence: terminal, of two to several, long-hairy, erect branches ending in small clusters of two to several (under ten) semi-erect, pink, 2.5 - 4 cm diameter, radially symmetric, hairy-stalked flowers. The inflorescence branches usually have a whorl of small bracts just below the cluster of flower stalks, and the long hairs covering the branches may have stalkless glands at their base. Sepals: five, alternate with petals, green, hairy (including softly long-hairy edges), non-glandular, about 1 cm long, with very slender tip and stiff bristle at apex. Petals: five, pink, non-toothed, 1.2 - 1.8 cm long, about 1 cm wide, inversely egg-shaped with narrowed base, and wide, somewhat flat to shallowly rounded tip. Next to the base of each petal there is a gland, thus making a ring of five glands alternate the petals. Stamens: ten in two series, all fertile, with filaments widened at base, and large anthers (at least 2 mm long). The ring of five longer stamens are aligned with the petals, while the five shorter stamens are alternate with the petals, and thus aligned with the glands. Pistil: with a single, deeply five-lobed, superior ovary; one elongated and minutely hairy style column; and five linear stigmas. Fruit: five, erect, hairy, non-glandular, 3 - 4 cm long, single-seeded, rounded base, beaked, nutlike segments surrounding remnant elongated style column of each flower. Each nutlike segment has a 5 - 8 mm long, narrowed beak at its tip, which is attached to the lower part of the style column, and then is pulled upwards by the coiling outer wall of the style column, yet stays attached to the entire fruiting structure and ejects the seed from the main body of the nutlike segment. Root system: of stout, stem-like rhizomes.
Similar species: Geranium maculatum is the only native perennial species of Geranium in our area with petals more than 1.1 cm long and anthers at least 2 mm long. There are two non-native species that may appear similar to it, but G. sanguineum differs by having numerous stem leaves, only one flower per inflorescence stalk, notched petals, and a shorter (under 5 mm) beak on the fruit. The non-native G. pratense also has similarly stout rhizomes, large petals and anthers, and normally only a single flower, but the flower stalks, sepals, and beak of the fruit are finely glandular-hairy, plus the flowers hang downward after blooming. A third species, G. robertianum, is somewhat similar due to its petals being over 1 cm long, but it is an annual (or biennial) with weak roots, compound leaves, flowers in pairs, and wrinkled nut-like portions of the fruit which fully separate from the style column and have two long apical beaks attached to them.
Flowering: April to July
Habitat and ecology: Common in woodlands and savannas, thriving in open woods, and also able to survive severe levels of disturbance.
Occurence in the Chicago region: native
Etymology: Geranium comes form the old Greek name for a crane geranos, referring to the long beak of the fruit resembling a crane's bill or beak. Maculatum is Latin for spotted, which may refer to the dot-like glands at the base of the petals.
Perennial from a stout rhizome, with a few long-petioled basal lvs, these pedately cleft into 5-7 cuneately laciniate segments; stems erect, 3-7 cm, with a single pair of short-petioled lvs; fls few-several; cal and pedicels pubescent but not glandular; pet pink (white), 12-18 mm, entire; mature pedicels suberect; frs erect, 3-4 cm, including the 5-8 mm stylar beak. Common in woods; Me. to S.C. and n. Ga., w. to Man., Neb., and ne. Okla. Apr.-June.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.