_Continental Range_—From Nova Scotia, southward throughout Canada, and New England, to Florida; westward to Minnesota, and Texas. _New England Range_—Maine, common; New Hampshire, very common; Vermont, common; Massachusetts, common; Rhode Island, very common; Connecticut, common. [Illustration: =The Slender Ladies’ Tresses.= (_Gyrostachys gracilis._) Showing the spindle-shaped roots; this species is closely allied with _G. simplex_, which produces but a single tuber.] VII Listera R. Brown, 1813[80] 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[81] 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[82] 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.