white avens (EwA Guide to the Plants of the Fells (US))

white avens

Geum canadense

Summary ⁷

Geum canadense (white avens) is a plant in the rose family, Rosaceae. It is widespread across much of Canada, the United States, and Mexico.

Description ⁸

This perennial plant is about 1½–2½' tall, branching occasionally. The upper stems are light green and pubescent, while the lower stems are often brownish green and coarsely hairy. These stems are round in circumference, rather than angular. There are both basal leaves (produced during the spring) and alternate cauline leaves. The basal leaves are produced in a low rosette up to 6" across. The lower cauline leaves are trifoliate, while the upper cauline leaves are usually simple; they are rather variable in shape. Both simple leaves and leaflets of the compound leaves are up to 4" long and 3" across, becoming smaller as they ascend the stems. They are medium green, lanceolate to oval-ovate, coarsely serrated, and often cleft into 3 major lobes. Their margins are often shallowly cleft or incised as well. The basal leaves are similar to the cauline leaves, except they are dark green and odd-pinnate with more than 3 leaflets. The wrinkled upper surface of each leaf is either hairless or it has scattered hairs that are very short and bristly; the lower surface is either hairless or it has a few hairs along the major veins. The lower leaves have stout petioles up to 1" long, while the upper leaves have either short petioles or they are sessile. At the base of each petiole, there are a pair of leafy stipules up to ½" long that are usually toothed along their margins. Each upper stem often terminates in an inflorescence of 1-3 flowers; sometimes individual flowers are produced from the axils of the upper leaves. The peduncles are up to 3" long and finely pubescent; they divide into shorter pedicels when there is more than one flower in the inflorescence. Each flower is about ½" across, consisting of 5 bright white petals, 5 triangular green sepals, and numerous stamens surrounding a cluster of green carpels with elongated styles. The sepals are the same length or shorter than the petals; they are initially spreading, but curve downward with age. The anthers of the stamens are initially white, but they soon turn brown. The receptacle of each flower (the surface underneath the carpels) is pubescent. The blooming period occurs during the summer and lasts about 1-2 months. There is no noticeable floral scent. Each flower is replaced by a spheroid cluster of achenes with persistent styles that are hooked at their tips. This fruiting cluster spans about ¾" across; it is initially green, but eventually turns brown. The root system consists of a taproot and rhizomes; from the latter, vegetative offsets can be produced. This plant occasionally forms loose colonies. Cultivation

Fontes e Créditos

(c) Dan Mullen, alguns direitos reservados (CC BY-NC-ND), http://www.flickr.com/photos/8583446@N05/4688428574
(c) Bob O'Kennon, alguns direitos reservados (CC BY-NC), uploaded by Bob O'Kennon
(c) smwhite, alguns direitos reservados (CC BY-NC), uploaded by smwhite
(c) ajlogan, alguns direitos reservados (CC BY-NC), uploaded by ajlogan
(c) Lori A Owenby, alguns direitos reservados (CC BY-NC), uploaded by Lori A Owenby
Sem direitos reservados, uploaded by Dave Behm
(c) Wikipedia, alguns direitos reservados (CC BY-SA), http://en.wikipedia.org/wiki/Geum_canadense
(c) John Hilty, alguns direitos reservados (CC BY-NC), http://eol.org/data_objects/29443365