MIDDLESEX FLORA. 51 



INULA, L. 



I. HELENIUM, L. ELECAMPANE. 



Generally distributed, but not very common. July-Aug. Nat. 

 from Eu. 



PLUCHEA, Cass. 



P. camphorata, DC. SALT-MARSH FLEABANE. 

 Common along salt marshes. Aug. 



SILPHIUM, L. 



*S. laciniatum, L. KOSIN-WEED. COMPASS-PLANT. 



Concord, int. from 111. by Minot Pratt. July. 

 */#. terebinthinaceum, L. PRAIRIE DOCK. 



Concord, int. from 111. by Minot Pratt. July-Aug. 



PARTHENIUM, L. 

 P. Hysteropliorus, L. 



Lowell, ' ' dumps " (Dr. C. W. Swan) . Sept. Adv. from the South . 

 For description, see Wood's Bot. & Fl. 



IVA, L. 



1. frutescens, L. 

 Common along salt marshes and tidal streams. Aug. 



AMBROSIA, Tourn. 



A, artemisiaefolia, L. ROMAN WORMWOOD. RAGWEED. 

 Very common. A form with fertile spikes from Maiden (F. S. 

 Collins) . July-Sept. 



XANTHIUM, Tourn. 



X. strumarium, L. COCKLEBUR. 



N. Chelmsf ord, wool-waste (Kev. W. P. Alcott ; specimen in herb. 



of). Aug. Adv. from Eu. 

 X. Canadense, Mill., var. echinatum, Gray. 



Maiden and Medford (F. S. Collins) ; Westford, near woollen-mill 



(Dr. C. W. Swan). More common near salt marshes. Aug. 

 X. spinosum, L. SPINY CLOTBUR. 



Chelmsf ord, Lowell, Dracut and Westford (Dr. C. W. Swan). Aug. 



Int. in wool from Trop. Am. 



ECHINACEA, Moench. 



*E. purpurea, Moench. PURPLE CONE-FLOWER. 

 Centralville, Lowell (Dr. C. W. Swan); Waltham List. July. 

 Adv. from the West. 



