GENUS 19. 



ORCHID FAMILY. 



565 



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



Fig. 1391. 



Ophrys cernua L. Sp. PL 946. 1753. 

 Spiranthes cernua L. C. Rich. Orch. Ann. 37. 1817. 

 Gyrostachys cernua Kuntze, Rev. Gen. PL 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'-S' 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 parviflora 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'-i,s' tall, leafy below, minutely pubescent 

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



5. 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 2j'-6T long, persistent; 

 spike strongly spiral, 2i'-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 I. gracile has been described. 



