7o 



BOTANICAL GAZETTE. 



[ March, 



To those who may not have chanced to see the kind note 

 of the editors of the Gazette (xiii. 327), setting forth my 

 wishes, it may be said that the call was for at least the twenty 

 worst weeds in any locality or territory which any one would 

 be pleased to report upon. In nearly all instances the weeds 

 were given their rank as to injuriousness, and from such re- 

 ports the present article is made up. Following each species 

 will be observed a fraction : the numerator indicates the num- 

 ber of times the species appears in the twenty-five lists, 

 while the denominator is the sum of all the rank numbers. 

 Thus, Agropyrum repens has the fraction ¥ 8 T , which indicates 

 that this "quack-grass" or "quick-grass" appears eight 

 times in the twenty-five lists, and that the rank total is thirty- 

 one, the respective ranks being 5, 1, 4, 3, 9, 2, 5, and 2. 

 another illustration, Chrvsanthemum Leucanthemum, or 

 "ox-eve," "ox-eye daisy," or " bulFs-eye," also has eight 

 mentions, but the sum of the rank figures, 4, 16, 17, 9, 5, II, 

 6, 12, is eighty. It will be seen that the fraction following 

 each species therefore indicates the rank of the injuriousness 

 of each sort, as far as averages can do it in connection with 

 the wide or limited distribution of the species. The thirty- 

 four are as follows, arranged alphabetically : 



Agropyrum repens, 3 ? r . 



Amarantus albus, f\. 



Amarantus retroflexus, tVV 



Amarantus spinosus, ^j. 



Ambrosia artemesiaefolia, T W- 



Ambrosia trifida, fy. 



Arctium Lappa, -^gj. 



Asclepias Comuti, ['$. 



Bidens frondosa, -fy. 



Brassica Sinapistrum, 



Capsella Bursa-pastoris, j/g-. 



Cenchrus tribuloides, ^\. 



Chenopodium album, y 1 ^. 



Chrysanthemum Leucanthemum, ^ ff . Taraxacum officinale, ," 



Datura Stramonium, 7 %. 

 Erigeron annuum, -£$. 

 Hypericum perforatum, fa 

 Panicum Crus-galli, 7 6 T . 

 Panicum sanguinale, l±. 



Portulaca oleracea, 2 2 (fr- 

 Rumex Acetosella, l\. 

 Ramex crispus, T \^. 

 Rumex obtusifolius, z \. 

 Setaria glauca, fo 

 Setaria viridis, ^ 7 . 

 Sol ami m Carolinense, fo. 

 Solanum rostratum, fa. 



Convolvulus sepium, y T . 

 Cnicus arvensis, ^. 

 Cnicus lanceolatus, r \. 



Vernonia fasciculata, ^. 



Xanthium Canadense, 4 8 8 . 

 Xanthium stramonium, ^ 



The numerators may fairly indicate the prevalence of the 

 weed. Thus Portulaca oleracea, the common purslane or 

 "puslev. M has the most frequent mention, namely, 20 out of 



the 25; while Solanum rostratum, the Texan nettle or 

 beaked horse-nettle, is only five times reported in the list. 



