13S Cincinnati Society of Natural History. 



The large number of flower-heads produced by each phint, and 

 the number of flowers in each head, produce seeds that in tlie 

 aggregate assume enormous numbers. One plant u{ Jasciciilata has 

 been recorded as possessing no less than 3.290 flower-heads/^ 

 and these, if producing only twenty seeds eac!i, a very moderate 

 estimate, would give 65,800 fruits. This, as ihe product of a single 

 plant, would be sufficient to stock a lar^e tract of country. Each 

 seed is provided with a number, about forty, capillary bristles, and 

 these when ripe spread out into a head which is readily caught by 

 the wind. As the fruits ripen the involucral scales spread, and 

 leave the seeds standing free in tiie center. Ripening at a period 

 when the winds generally blow strongly, there is every opportunity 

 for them to be carried far and wide. Hearing this in mind it seems 

 a little strange that so many of tiie species should be as local as 

 they are. It may probably be accounted for by the late flowering 

 habits of some, but more likely by the absence of certain necessary 

 features in the surroundings. 



It is natural to suppose two avenues by which the plants entered 

 the United States. One by the way of the Florida Peninsula 

 through the West India Islands from the mainLmd of Si»uih 

 America; and the other by way of Mexico, into Texas and thence 

 nortinvard. Those entering by the first avenue would naturally 

 spre.id northward along the peninsula, and mainly along the 

 Atlantic Coast. They would most probably be plants loving damp or 

 swampy places, such being the character of the ground they would 

 have to cross. If spreading to the westward they would be mainly 

 confined to the coast region. Those entering from Mexico would 

 f.)llow the streams, or even slightly encroach upon the adjacent 

 higher grounds. The species entering from Mexico would migrate 

 rorthward and eastward, mainly because the prevailing winds are 

 from the south and west. 



That the wind is a most potent agent for their dissemination can 

 s arcely be denied. Baron Eggers says in regard to some of the 

 West India Islands (Flora of the St. Croix and Virgin Iblands), 

 that until about August the winds blow constantly from the north- 

 east. But between August and November they become unsteady 

 and uncertain. This is the season for hurricanes and it is also 

 about the season when Vcrnonia seeds are ripe. Thus, if then 

 taken up by the winds, they would be carried a long'way and be 



* Botaniial Gazetit' II, p. 121. 1 



