FLORA OF BURLINGTON AND VICINITY 29 



L. Loeselii (L.) Richard. Fen Orchis. Damp fields; occasional. June, 



July. 



LISTERA R. Br. TwaybladE 



L, cordata (L.) R. Br. Heart-leaved Twayblade. Sphagnum bogs; 

 rare. June. South Burlington, (Jones). 



MICROSTYLIS (Nutt.) Eaton. Adder's Mouth 



M. imifolia (Michx.) BSP. Green Adder's Mouth. Open woods; occa- 

 sional. July. 



ORCHIS (Tourn.) L. 



0. spectal)ilis L. Showy Orchis. Rich moist woods; occasional. May, 

 June. 



POGONIA Juss. 



P. affinis Aust. Small Whorled Pogonia. One plant in woods at Fair- 

 holt, Burlington, (Mrs. Holt). May, June. 



P. ophiog-lossoides (L.) Ker. Rose Pogonia, Snake-mouth. Bogs; fre- 

 quent. June, July. 



P. Tcrticillata (Willd.) Nutt. Whorled Pogonia. Woods; rare. May, 

 June. Colchester, (Bobbins, Torrey, Ross); Burlington, (Jones). 

 Has been found in two or three different stations at intervals of 

 several years. 



SPIRANTHES Richard. Ladies' TrESSEs 



S. ceruTia (L.) Richard. Nodding Ladies' Tresses. Wet soil; common. 

 Aug., Sept. 



S. gracilis (Bigel.) Beck. Slender Ladies' Tresses. Sandy woods and 

 plains; occasional. July, Aug. 



S. Romanzoffiaua Cham. Swamps and moist soil; rare. July, Aug. 

 Colchester, (Griffin). 



SALICACEAE. WILLOW FAMILY 



POPULUS (Tourn.) L. Poplar. Aspen 



P. alba L. White Poplar, Silver-leaved Poplar, Abele. Frequent as 

 an escape from cultivation. Apr., May. Only pistillate trees occur. 



P. balsamifera L. Balsam Poplar, Tacamahac. Wet ravines and bor- 

 ders of rivers; frequent. Apr., May. 



