1906] House, Observations on Pogonia verticillata 19 



OBSERVATIONS UPON POGONIA (ISOTRIA) 

 VERTICILLATA. 



(Plate 65). 



Homer Doliver House. 



A large colony of the rare orchid Pogonia verticillata (Willd.) 

 Nutt. was recently observed near Washington, D. C, by Mr. Joseph 

 H. Painter of the National Museum, and the writer. It was discovered 

 that many if not all of the plants were connected in groups of two to 

 four or more plants by perennial horizontal rhizomes, one to six feet 

 in length. In the accompanying photograph (plate 65) a small group 

 is shown, consisting of two mature flowering plants and a young plant 

 without a flower, connected by a single root-system, the entire extent 

 of which measured about three feet. There is also shown a single 

 plant with two flowering stems. 



Inquiry revealed the fact that the nature of the roots of this orchid 

 is almost unknown, even to many of those familiar with it growing. 

 In systematic literature we find the following scanty or misleading 

 descriptions of the root of Pogonia: — Beck, "perennial" ; Darlington, 

 "root of fleshy fibers" ; A. 

 Gray, "root a cluster of 

 fibers"; Britton's Manual, 

 "rootstock and fibrous 

 roots, — stems from long 

 fleshy roots." Rafinesque, 

 Eaton and Wood, do not 

 mention the root. Recent- 

 ly, J. G. Hall (Rhodora 

 7 : 49. M. 1905) mentions 

 having seen roots of this 

 species " 18 to 20 feet long." 



The perennial rhizome 

 of Pogonia verticillata is 

 horizontal and gives rise 

 to new stems by buds which when partially developed give off 

 fibrous roots, just above the origin of the new stem, similar in all 

 respects to the somewhat fleshy, brittle rootstocks. These roots, 



