254 ORCHIDACEAE 



Pa. Northampton, Lehigh, Bucks, Delaware and Chester counties. 

 Tertiary, o: Cretaceous, rare in Bucks Co., Pa.: Older Formations 

 not common. 153-204 days. Sea level-500 ft. 



13. Arethusa L. 

 1. A. bulbosa L. In bogs: Newf. to Ont. and Minn., south to 



N. Car. and Ind. 



Conn. Rare and local. 



N. Y. Rare and local in Dutchess Co., increasing and frequent 

 southward, particularly on L. I. Not recorded from S. I. 



N. J. Scattered north of the moraine in Sussex, Morris, Essex and 

 Bergen counties, and common south of the " fall line "; appar- 

 ently wanting in the Piedmont region in Hunterdon, Somerset 

 and Mercer counties. 



Pa. Wayne, Northampton and Chester counties. 



Tertiary, common: Cretaceous, less common: Older Formations, 



confined to the glaciated area except in Pa.* 144-204 days. Sea 



level-993 ft. 



14. Limodorum L. 



1. L. tuberosum L. In bogs and meadows: Newf. to Ont. and 

 Minn., south to Fla. and Mo. 



Throughout the range. Apparently wanting or at least very 

 rare on the Piedmont Plateau in N. J. 



15. Serapias L. (Epipactis R. Br.) 

 1. Serapias Helleborine L. (E. viridiflora (Hoffm.) Reichb.). 

 Que. and Ont. to Mass., N. Y., N. J. and Pa. 



Known only from a single station near Plainfield, Union Co., N. J., 

 which has an elevation of about 100 ft., a growing season of 162 days, 

 and is on or near the terminal moraine. 



16. Ibidium Salisb. {Gyrostachys Pers. Spiranthes Rich.). 



Flowers 3-ranked; stems not twisted or slightly so. 



Sepals and petals more or less connivent into a hood. 1. /. slrictum. 



Lateral sepals separate, free. 



Spike about 5 cm. long, 8-10 mm. thick; lip with a truncate 



base and 2 small spreading callosities. 2. /. plantagineum. 



Spike 10-15 cm - l° n g. 12-20 mm. thick; lip with a cuneate 



base and 2 stout reflexed callosities; flowers yellowish. 3. I. cernunm. 

 Flowers merely alternate, appearing secund from the spiral twisting 

 of the stem. 



* See Introduction paragraph 7. 



