254 TWENTY-FIRST REPORT. 



17. IRIDIUM Salisb. Ladies' Tresses. 



Flowers apparently in a single rank, secund ; roots fasciculate ; 



plant of dry places 1 I. gracile. 



Flowers apparently in several ranks; plants of wet soil or 

 moist woods. 

 Flowering early (June — July) ; lip pale yellow; leaves about 



1 cm. wide, oblong-Ian eeolate 2. I. plantigineum. 



Normally flowering later (July — Oct.) ; leaves linear- 

 lanceolate. 



Lip contracted below the apex; sepals and petals 



not distinctly spreading at apex 3. /. strictum. 



Lip oblong, not contracted below apex; sepals and 



petals distinctly spreading at tip 4. /. cernuum. 



1. L Ibidiuxn gracile (Bigel.) House, (slender). 



Spiranthes gracilis (Bigel.) Beck. 



Gyrostachys simplex Kuntze. 



Dry fields and open woods. Occasional throughout. July — Sept. 

 Specimens examined: — Gratiot Co. (C. A. Davis, Sept., 1894); St. Clair Co. (C. 

 K. Dodge, Aug., 1892) ; Muskegon Co. (C, D. McLouth, Aug., 1901) ; Marquette Co. 

 (B. Barlow, July, 1901); Macomb Co. (Dr. D. Cooley, 1848); Iron Co. (C. A. Davis, 

 1905); Gogebic Co. (E. A. Bessey, 1919). 



Reported from: — Kent Co. (Emma Cole), "rare".; Jackson Co. (H. S. Camp); 

 Kalamazoo Co. (Tut'hill); Choboygan Co. (Kofoid and Beardslee); Calhoun Co. (C. 

 C. McDermid); Emmet Co. (C. W. Swift); Lenawee Co. (C. Billington). 



2. Ibidium plantigineum (Raf.) House, (plantain-like). 



Spiranthes lucida (H. H. Eaton) Ames. 

 Spiranthes latifolia Torr. 

 Moist banks and woods. Apparently rare. June — July. 

 Specimens examined: — Ionia Co. (C. F. Wheeler), "in swamps, rare". 

 Reported from: — Calhoun Co. (C. E. Barr); Jackson Co. (H. S. Camp); Drum- 

 mond's Island; Roscommon Co. (Beal's Cat., 1904). 



3. Ibidium strictum (Rybd.) House, (stiff, upright). 



Spiranthes romanzojfiana Cham, in part. (Gray's Man., 7th ed.). 

 Gyrostachys stricta Rydb. 

 Boggy soil, throughout. July — Sept. 

 Specimens examined: — Roscommon Co. (E. A. Bessey and H. T. Darlington, July, 

 1916), No. 426; Charlevoix Co. (C. F. Wheeler, Sept., 1894); Newaygo Co. (E. A. 

 Bessey, Aug., 1916, No. 891); Mason Co. (Aug., 1895); Crawford Co. (G. H. Hicks. 



