Part 41

Listera

R. Brown, 1813

LISTER’S TWAYBLADE

The generic name, Listera, is in honor of Martin Lister, 1638(?)-1712, a correspondent of Ray.

Small orchids with fleshy-fibrous roots. =Anther=, 1. =Labellum= 2-cleft, longer than petals. =Sepals= and =petals= nearly alike. =Flowers= in terminal raceme, spurless. =Anther= erect, joined to column, without a lid. =Pollinia=, 2, united to gland, powdery. =Stem= 3-10 inches high. =Leaves=, 2, opposite, near the middle of the stem, 1-2 scales below.

Continental Range—In moist woodlands and boglands from Alaska, southward to Florida; westward to the Pacific coast. There are 12 species or more belonging to the north temperate zone which are closely related to species of Gyrostachys and Peramium, save in the herbaceous foliage.

North American species north of Mexico 8 New England species 3 Hoosac Valley species 1-2

New England species:

1. L. convallarioides (Swartz) Torrey, 1800-1826. 2. L. auriculata Wiegand, 1899. 3. L. cordata (Linnæus) R. Brown, 1753-1813.

1.—LISTERA CONVALLARIOIDES (Swartz) Torrey, 1800-1826

BROAD-LIPPED TWAYBLADE

The specific name, convallarioides, refers probably to a supposed resemblance of this species to Convallaria, the Lily-of-the-Valley.

Small woodland orchid, with fleshy-fibrous roots. June 9th-August 17th.

=Flowers= purplish-yellow, 3-15 spurless, subtended by acute bracts, ¼-⅓ inch long. =Labellum= wedge-shaped, broader than sepals or petals, produced into 2 distinct lobes at the apex, notched in center, ornamented with tooth at the base. =Sepals= and =petals= linear-lanceolate. =Stem= 4-10 inches high. =Leaves= 2, nearly orbicular in the middle of stem, opposite, smooth, obtuse at the apex, 3-9 nerved.

Continental Range—From the wooded coast Unalaska, southward throughout the Canadian provinces, to North Carolina; westward to the fir-forests of Idaho, Washington, Wyoming, Sierra Nevada Mountains, and the Bay region of California.

New England Range—Maine, common; New Hampshire, frequent; Vermont, infrequent; Massachusetts, doubtfully reported.

2.—LISTERA AURICULATA Wiegand, 1899

AURICLED TWAYBLADE

The specific name, auriculata, from auriculum, ear, refers to the auricled base of the labellum and leaves of this species.

Small cedar swamp orchid, with fibrous roots. July.

=Flowers=, many in slender raceme. =Labellum= slightly ciliate, oblong, broadest at the auricled base, cleft ¼-⅓ its length. =Sepals= lanceolate; =petals= oblong-linear, longer than the ovary, spreading, obtuse. =Stem= 4-7 inches high, slender. =Leaves= large, oval, or elliptic-ovate, borne above the middle of the stem.

Continental Range—From Quebec, southward to Maine and New Hampshire.

New England Range—Maine, rare; New Hampshire, rare.

3.—LISTERA CORDATA (Linnæus) R. Brown, 1753-1813.

HEART-LEAVED TWAYBLADE

The specific name, cordata, refers to the cordate or heart-shaped leaves.

Small, moist woodland orchid, with fibrous roots. June 27th-July 30th-August 8th.

=Flowers= minute, purplish, in a loose raceme, ½-2 inches long, 4-20 flowered, pedicels bracted, ⅙ inch long. =Labellum= 2-cleft, narrow, with a tooth on each side at the base. =Sepals= and =petals= oblong-linear. =Stem= slender, 3-10 inches high. =Leaves= 2, heart-shaped, or cordate ½-1 inch long.