GENUS 19. 



ORCHID FAMILY. 



565 



3. Ibidium cernuum (L.) House. Nodding or drooping Ladies'-tresses. 



Fig. 1391. 



Ophrys cernua L. Sp. PI. 946. 1753. 

 Spirant hes cernua L. C. Rich. Orch. Ann. 37. 1817. 

 Gyrostachys cernua Kuntze, Rev. Gen. PI. 664. 1891. 

 Spiranthes odorata Lindl. Gen. & Sp. Orch. 467. 1840. 

 Gyrostachys ochroleuca Rydb. in Britton, Man. 300. 1901. 

 /. incurvum Jennings, Ann. Car. Mus. 3 : 483. 1906. 

 /. cernuum House, Bull. Torr. Club 32: 381. 1905. 



Stem 6'-25' high (rarely taller), usually pubescent 

 above, mostly bearing 2-6 acuminate bracts. Leaves 

 nearly basal, linear-oblanceolate or linear, $'-14' 

 long, the blade narrow, the petiole 2'-io' long; spike 

 4'-5' long, 6"-7" thick; flowers white or yellowish, 

 fragrant, nodding or spreading, about 5" long, in 

 3 rows; lateral sepals free, the upper arching and 

 connivent with the petals; lip oblong, or sometimes 

 ovate, the broad apex rounded, crenulate or crisped ; 

 callosities nipple-shaped, straight, hairy. 



In wet meadows and swamps, Newfoundland to On- 

 tario, South Dakota, Florida and New Mexico. Wild 

 tube-rose. Screw-auger. Aug.-Oct. 



4. Ibidium ovale (Lindl.) House. Small-flow- 



ered Ladies'-tresses. Fig. 1392. 



Spiranthes ovalis Lindl. Gen. & Sp. Orch. 466. 1840. 



5. cernua parvi flora Chapm. Fl. S. U. S. Ed. 3, 488. 1897. 

 Gyrostachys parviflora Small, Fl. SE. U. S. 318. 1903. 

 Spiranthes parviflora Ames, Orch. 137. 1909. 



Ibidium ovale House, Muhlenbergia i : 128. 1906. 



Stem 4/-I5' tall, leafy below, minutely pubescent 

 above. Leaves broadly linear to linear-oblong, ij'-6i' 

 long, or . the upper smaller ; spike slender, compact, 

 tapering upward, the bracts shorter than the flowers; 

 flowers small, about 2" long, white, nodding; lateral 

 sepals free, lanceolate; lip about 2" long, ovate, narrow 

 at the apex or acute ; callosities slender, curved. 



In woods and swamps, Ohio to Missouri, Georgia and 

 Louisiana. Sept.-Oct. 



5. Ibidium vernale (Engelm. & Gray) House. 

 Linear-leaved Ladies'-tresses. Fig. 1393. 



Spiranthes vernalis Engelm. & Gray, Bost. Journ. Nat. Hist. 

 5:236. 1845. 



S. neglecta Ames, Rhodora 6: 30. pi. 51. 1904. 

 Gyrostachys linearis Rydb. in Britton, Man. 300. 1901. 

 Ibidium vernale House, Bull. Torr. Club 32 : 381. 1905. 



Stem slender, 6'-22' high, usually copiously glandular- 

 pubescent above, leafy. Leaves linear, or somewhat 

 tapering to both ends, mostly 2$'-6T long, persistent; 

 spike strongly spiral, 2|'-6' long, mostly 4"-6" thick ; 

 bracts much longer than the ovaries ; flowers yellowish ; 

 lip 3"~3$" long, ovate, much shorter than the median 

 sepal; callosities slender, often hooked at the tip. 



In dry or wet soil, Massachusetts to Florida and New 

 Mexico, north in the Mississippi Valley to Illinois and Kan- 

 sas. Aug.-Sept. A hybrid with /. gracile has been described. 



