(A) Heart-leaved Twayblade (Listera cordata) belongs to a genus containing five species.
Like most of the orchids, they are largely or wholly dependent upon insect aid for fertilization. The weight or shock of an alighting insect on the broad lip causes a small gland within the flower to rupture and cover the pollen, just below, with a sticky fluid that causes it to adhere to the head or body of the insect and thus be transferred to the next flower.
The stem of this species is from 3 to 10 in. high. At the top is a few-flowered raceme; the sepals and petals are similar and spreading; the lip is drooping, longer, two-cleft and madder-purple in color. This species flowers during June and July in swampy woods from N. J. to Colo. and northward to the Arctic coast.
(B) Twayblade (Liparis lilifolia) although having the same common name, is of a different genus. It is a more attractive plant, having two broad basal leaves and larger flowers with a broad ovate lip. It grows in woodland from Me. to Minn. and southward.
BIRTHWORT FAMILY
(Aristolochiaceæ)
A small family of low herbs or twining vines, with but two genera and few species.
Wild Ginger (Asarum canadense) may be found flowering in rich woods during April and May, from Me. to Mich. and southward. It has two large, heart-shaped leaves on long petioles from the base; deep green above and lighter below, soft, wooly, and handsomely veined.
The leaves are very beautiful, but it is the solitary flower that makes this plant so interesting. Small, dully colored, on a weak, short stem that barely raises it above ground and often leaves it concealed by the dead leaves that carpet the woods in early spring.
The flower is bell-shaped, with three short, sharply-pointed spreading lobes; six stamens with short anthers and a thick style with six radiating stigmas. Another species (grandiflorum), found in Va. and N. C., has but one leaf and flowers twice as large, or two inches in length.