ORCHID A CEAE. 3O I 



9. Gyrostachys gracilis (Bigel.) Kuntze. SLENDER LADIES' TRESSES. (I. F. 

 f. 1127.) Stem slender, 2-6 dm. high, from a cluster of spindle-shaped tuberous 

 roots, glabrous, or rarely pubescent above, bearing small deciduous bracts. Leaves 

 basal, obovate, or ovate-lanceolate, petioled, the blades 1-5 cm. long, 8-20 mm. 

 wide, mostly perishing before the flowering season; spike 2-6 cm. long, 8-12 mm. 

 thick, loose, usually much twisted; flowers white, fragrant, 4-5 mm. long; sepals a 

 little longer than the lip; lip alxxit 4 mm. long, oblong, dilated and crenulate or 

 wavy -crisped at the apex, usually thick and green in the middle, white and hyaline 

 on the margins; callosities small, nipple-shaped. In dry fields and open woods, 

 N. S. to Minn., Fla., La. and Kans. Aug.- Oct. 



18. Ll'STERA R. Br. 



Small herbs, with fibrous or sometimes rather tie shy -fibrous roots, bearing a pair 

 of opposite green leaves near the middle, and i or 2 small scales at the base of the 

 stem. Flowers in terminal racemes, spurless. Sepals and petals nearly alike, 

 spreading or reflexed, free. Anther without a lid, erect, jointed to the column. 

 Pollinia 2, powdery, united to a minute gland. Capsule ovoid or obovoid. [Name 

 in honor of Martin Lister, 1638 (P)-I7I2, a correspondent of Ray.] About 12 spe- 

 cies, natives of the north temperate and arctic zones. Besides the following, an- 

 other occurs in northwestern North America. 



Lip broadly wedge-shaped, retuse or 2-lobed at the apex. 



Leaves oval ; pedicels and ovaries glandular. I. L. convallarioides. 



Leaves reniform ; pedicels and ovaries glabrous. 2. L. Smallii. 



Lip oblong or linear. 



Lip broad, 2-cIeft V-\& its length ; base auricled. 3. L. auriculata. 



Lip 2-cleft about J^ its length. 



Lip twice as long as the petals, with lateral teeth. 4. L. cordata. 



Lip 4-8 times as long as the petals, with auricles at the base. 



5. L. australis. 



1. Listera convailarioides (Sw.) Torr. BROAD-LIPPED TWAYBLADE. (I. F. 

 1 1128.) Stem 1-2 dm. high, glandular-pubescent above the leaves. Leaves 

 smooth, round-oval or ovate, obtuse or apiculate at the apex, sometimes slightly 

 rounded at the base, 3-9-nerved. Raceme 3-7 cm. long, loosely 3-12-flowered; 

 flowers greenish yellow; pedicels filiform, glandular, bracted, 6-8 mm. long; petals 

 a ad sepals linear-lanceolate, much shorter than the lip; lip wedge-shaped, retuse at 

 the dilated apex, generally with a tooth on each side at base; column elongated, 

 but shorter than the lip, a little incurved, with 2 short projecting wings above the 

 anther. In woods, N. S. to Alaska, south to Vt., Mich., and Cal. June-Aug. 



2. Listera Smallii Wiegand. SMALL'S TWAYBLADE. (I. F. f. 11280.) Stem 

 slender, 15-20 cm. high, glandular above the leaves. Leaves at or below the mid- 

 dle of the stem, ovate-reniform, apiculate or short-acuminate; raceme open, rachis 

 glandular, but pedicels and ovaries glabrous or nearly so; sepals and petals lan- 

 ceolate, longer than the ovary; lip large, 9 mm. long, broadly obovate or wedge- 

 shaped, broadly 2-lobed at the apex and with prominent lateral teeth near the base; 

 column rather short and thick. In damp woods, in the mountains from Penn. to 

 N. Car. June-Aug. [Listera reniformis, Small, not G. Don.] 



3. Listera auriculata Wiegand. AURICLED TWAYBLADE. Stem slender, 10- 

 rS cm. high, glabrous below, glandular above the leaves. Leaves large, 3.5-5 

 cm. long, oval or elliptic-ovate, borne above the middle of the stem; raceme 

 many-flowered; rachis pubescent, pedicels and ovaries glabrous; sepals lance-ovate; 

 petals oblong-linear, longer than the ovary, spreading, obtuse; lip slightly ciliate, 

 oblong, broadest at the auricled base, cleft -$ its length; column rather stout, 2.5 

 mm. long. In cedar swamps of Quebec, N. H. and Me. July. 



4. Listera cordata (L.) R. Br. HEART- LEAVED TWAYBLADE. (I. F. f. 1129.) 

 Stem very slender, glabrous or nearly so, 7-25 cm. high. Leaves sessile, cordate 

 or broadly ovate, mucronate, 1-2.5 cm - long; raceme rather loose, 1-5 cm. long, 

 4-20- flowered; flowers purplish, minute; pedicels glabrous, bracted, about 2 mm. 

 long; sepals ovate and petals oblong, scarcely 2 mm. long; Up narrow, often with 

 a subulate tooth on each side of the base, twice as long as the petals, 2-cleft, the 

 segments linear or getaceous and cjljolate; column very small, the clinandrium just 



