No. 14.] FLOWERING PLANTS AND FERNS. 391 



Rare. Waste ground: Southington (Weatherby & Bis- 

 sell), Fairfield (Eames). Aug. Introduced from the West. 

 The rhizome is medicinal. 



IVA L. Marsh Elder. Highwater-shrub. 



Iva oraria Bartlett (of the coast). 



Iva frutescens of Gray's Manual ed. 6, not L. 

 Highwater-shrub. 



Common on salt marshes and seashores. July — Sept. 



Iva xanthifolia Nutt. (having leaves like Xanthium, the Clot- 

 bur). 



Rare. Waste places: Naugatuck (A. E. Blewitt), Bridge- 

 port (Eames), New Milford (E. H. Austin). July — Sept. 

 Introduced from the West. 



AMBROSIA L. Ragweed. 

 Ambrosia bidentata Michx. (two-toothed). 



Rare. Bridgeport, in waste ground (Eames). Sept. 

 Fugitive from the West. 



Ambrosia trifida L. (three-cleft). 

 Great Ragweed. 



Moist places and alluvial flats. Usually rare; but local, 

 frequent or common along the larger rivers and in south- 

 western Connecticut. Aug. — Sept. 



The var. integrifolia (Muhl.) Torr. & Gray (having 

 entire leaves) is occasional with the typical form, 



A coarse and unsightly weed. 



Ambrosia artemisiifolia L. (having leaves like Artemisia, the 



Wormwood). 

 Ragweed. Hog-weed. Bitter-weed. Roman Wormwood. 



Common. Open places, especially in waste and cultivated 

 ground. July — Sept, 



A troublesome and pernicious weed in all soils. Its pollen 

 is said to cause hay fever. The plant is medicinal. 



XANTHIUM L. Clotbur. Cocklebur. 

 Xanthium spinosum L. (spiny). 

 Prickly or Spiny Clotbur. 



