Geranium maculatum is a perennial herb, to 60 cm tall, stems clustered, hairy (Yatskievych 2006), from a short, stout rhizome; rhizome dormancy broken by cold; leaf and flower buds form late in season following seed dispersal (Martin 1965).
Leaves opposite, few, mostly basal, stalk to 30 cm long on basal leaves, blade round in outline, palmately cleft into 5-7 wedge-shaped segments, lobed and toothed near tip; inflorescence with one pair of short-stalked leaves, veins deeply impressed; leaves appearing in April, new leaves often brownish-green.
Flowers pink-purple, 3 cm wide, petals 5, free, widest near tip, to 2.3 cm long, 1 cm wide, sepals 5 to 1.3 cm long including beaked tip; inflorescence of loose clusters, on stems to 7 cm long; pollinated by small bees feeding on both pollen and nectar; pollination must occur within about five hours, between the time the stigma becomes receptive and the time the petals are shed (Bertin and Sholes 1993; Mulcahy 1983); blooms May-June.
Fruit dry, each ovary segment (carpel) 1-seeded, hairy, style column linear, surrounded by persistent sepals, style column opens from base, each curling upwards, a seed attached to the detached end of the style, dispersed by forcible ejection. Seeds eaten by birds and small mammals. Foliage eaten by deer (Martin et al. 1951). Dispersal to and establishment in new sites in successional forest, contiguous to old regrowth stands has been calculated at a rate of 1.10 m/yr (Matlack 1994).
Wetland status: FACU.
Frequency in NYC: Occasional.
Habitat: Undisturbed moist to dry woods, shade tolerant. Generally in good quality soil (Gargiullo personal observation). In NYC found in soil with pH 5.4-5.6 (Gargiullo unpublished data).