ADVENTIVE AND FUGITIVE PLANTS. 55 



Arkansas valley, was first observed in Mobile in 1866. It has spread 

 along- the embankments of the railroads to the mouth of the Ohio 

 River, literally covering in many places the waste and uncultivated 

 grounds, and reaching out along byroads and borders of fields and 

 woodlands. In its northward spread this plant has largely taken the 

 place of the mayweed {Anthemis cot aid) ^ a European weed of early 

 introduction. Acanthospennum australe^ of the Antillean flora, has, 

 during the past thirty years, made its way along roadsides from the 

 coast of Georgia to western Florida and Alabama, and toward the banks 

 of the Mississippi River. As an example of a plant of more recent 

 advent, which has gained a firm hold among the weeds and native 

 plants of the waste heap, Melochia Mrsuta deserves to be mentioned. 

 First observed on recently turned soil at Mobile in 1875, and subse- 

 quently lost sight of for a number of years, it is now found to infest 

 cultivated and waste places widely in the Coast plain; and as it ripens 

 its seeds in abundance throughout the summer this weed proves most 

 troublesome and difiicult to eradicate. 



Somewhat over forty species of adventive plants have been recog- 

 nized in Alabama, fully one-half from Europe, and a small number 

 from the warmer regions of the Old World; one-third from the West 

 Indies and South America, and about one-sixth from the trans- 

 Mississippi region. The following weeds, classed among the adventive 

 plants, are most conspicuous by their abundance all over the State, 

 or, at least, in some one of the recognized botanical regions : 



Leptochloa mucronata. Cassia tora. 



Hackelochloa granular is. Sida rJiombifolia. 



Cyperus rotundus. Sida spinosa. 



Amaranthus retroflexus. Coronopus didi/mus. 



Amaranthus hybridus. Veronica pereyrina. 



Amaranthus spinosus. Veronica arvensis. 



Spergula arvensis. Lamium. amplexicaule. 



Porkdaca oleracea. Richardia scabra. 

 Cassia occidenUdis. 



FUGITIVE PLANTS. 



Under this designation are understood those immigrant plants which 

 have not firmly established themselves upon our soil and are liable to 

 succumb to the vicissitudes of climate and accidental changes in the 

 locality of their growth. In some instances their disappearance is to 

 be ascribed to the absence of the specialized insects necessary to their 

 fertilization and also to the occurrence of early and late frosts. They 

 are mostl}^ introductions coming with the ballast of ships and, show- 

 ing but a slight tendency to spread from the place where they were 

 landed, are mostly confined to ballast heaps. One hundred and fifty- 

 seven species of these fugitives have ))een observed in Alabama, 

 mostly on ])allast about the port of Mobile and on the shores of Mobile 



