Avens are herb-like, generally more or less rhizome-bearing herbs with usually numerous irregularly to pinnately divided or pinnately lobed basal leaves and few, alternate or opposite, mostly 3-lobed stem leaves. The flowers are complete, with the parts attached on a disk surrounding the ovary, mostly arranged several in bracted, usually open clusters, occasionally the flowers are single. The calyx has simple to sometimes cleft secondary bracts which are alternate with the 5 erect to bent backward lobes. The elongated floral axis below the calyx is free of the pistils, saucer-shaped to cup-shaped. The 5 petals are usually yellow but sometimes strongly pinkish-tinged to red or purplish, shorter to longer than the sepals. There are numerous stamens, borne in several series above (outside of) a (usually) ringlike or cuplike disc which is fused with, or free of, the elongated floral axis below the calyx. The pistils are numerous. The style is straight to bent or strongly bent at joints and jointed, often considerably elongate in fruit and then mostly with a soon withered terminal segment, at least the lower segment persistent on the achene. The seed is erect. The genus consists of about 50 species, mostly in the N. Temperate to Arctic Zone. A few species are found in S. America, and one in s. Africa.
Guide to Identify Presented Species of Genus Geum
FLOWERS YELLOW, BUTTERCUP-LIKE
G. macrophyllum Large-leaved Avens Stems 30-70 cm tall, spreading-stiff-hairy. Moist woods or meadowland.
Flowers yellow, 15-20 mm wide, with 5 rounded petals. Sepals bent back.
Leaves pinnately divided into 5-9 main leaflets, the final leaflet much larger.
FLOWERS PURPLE, NODDING, BELL-SHAPED
G. rivale Purple Avens Hairy plant, 40-60 cm tall, reddish. Stream banks, bogs, and wet meadows.
Flowers bell-shaped, nodding, purplish, 10-15 mm long, few in open cluster.
Leaves pinnately divided into 7-15 toothed leaflets, the 3 at the end much larger.