204. 
10. Pappus of retrorsely or antrorsely 
barbed awns or teeth (barbs not 
always apparent on immature 
flowers). (Also, achenes ciliate 
along the margins).........e++eee+++- Bidens 
10. Pappus of unbarbed teeth, of scales, 
or wanting. Expected (Heliopsis, 
Coreopsis). 
Iva 
Iva frutescens L. Marsh-elder, 
Highwater-shrub 
Java Farm and Ivy Neck. Moderately abundant in salt marshes, 
especially the more inland parts. Associate species: Distichlis 
spicata, Solidago sempervirens, Aster subulatus, Spartina patens, 
Hibiscus palustris. Higman 53, 114. 
Xanthium 
Xanthium pensylvanicum Wallr. Cocklebur 
(not included in Britton and Brown) 
Ivy Neck. One station: sandbar of cut-off pond on Rhode River 
shore of Cheston Peninsula. Hectare 5800. Associate species: Spartina 
alterniflora, Asparagus officinalis, Strophostyles helvola. Higman 
1030. 
Ambrosia 
1. Leaves entire or palmately cleft, opposite; staminate 
involucres unilaterally 3-ribbed; fruits 3 to 12 mm. 
IlefyVG GOS CULO OOOO OBO OOO OOOO OU OUUOU DOOD ODD ODDOOOOOOOUO iim isesbesYeln 
1. Leaves pinnately lobed to bi- or tri-pinnatifid, 
both opposite and alternate; staminate involucres 
obscurely radiate-veined; fruit smaller than 
ADOVE vearetele ss esc e ese ccc ceecetceseseeeccsccevcececscnee Ae artemisiifolia 
Ambrosia trifida L. Giant Ragweed 
Buffalo Weed 
Java Farm and Ivy Neck. Infrequent to moderately abundant along 
unshaded or partly shaded roads, tractor trails, and field margins. 
Wide variety of associate species. Higman 252, 311, 1025. 
