54 PLANT LIFE OF ALABAMA. 



It is often impossible to decide whether a plant should be considered 

 naturalized or native, particularly when, though it grows in distant 

 parts of the globe, every trace is obliterated of the time and manner 

 in which it may have been introduced. Such instances are found in 

 the Cherokee rose (Rosa laevigataj, the common gourd (Lagenaria vul- 

 garis), and the thornapple (Datura stramonium). The first, also at 

 home in eastern Asia, is said to have been found by the whites on 

 their first arrival at the villages of the Cherokees and Creeks; the sec- 

 ond, dispersed over the warmer regions of the Old World, was fre- 

 quently found about the habitations of the aborigines in the warmer 

 temperate and subtropical zone of this continent, and the last was met 

 with about the Indian villages on the banks of the James River in 

 Virginia. 



ADVENTIVE PLANTS. 



These are foreign plants which have gained a firm foothold only on 

 cultivated lands, or land abandoned by the cultivator, and arc rarely 

 found to stray beyond the waste places near his dwelling, lacking 

 power to hold their own in the struggle with the indigenous plants for 

 the possession of the soil. Strong feeders, of quick growth, these 

 adventive plants are dependent upon soils rich in available nitrog- 

 enous plant food, such as is provided by the tiller of the soil for his 

 crops or is accumulated in the rubbish about his habitations. Here 

 belong the host of weeds which infest fields, gardens, and meadows, 

 and consequently are in close connection with the cultural plant 

 formations. 



If it is difficult to draw the line between naturalized and indigenous 

 plants, it is not less so to decide whether a plant is thorough!}^ natu- 

 ralized or merely adventive. Some of the species, at first merely ad- 

 ventive, acquire speedily the ability to accommodate themselves to 

 their changed environment and thus become able to gain a firm hold 

 upon the soil among the indigenous plants, not infrequently spreading 

 widely if the proper opportunities for their dissemination exist. Some 

 of the plants of quite recent advent from distant shores offer striking 

 examples of this kind. The Japanese clover (Lespedeza striata), advent- 

 ive from eastern Asia, and first observed at the port of Charleston, 

 S. C. , during the second quarter of this century, has now spread over 

 thousands of square miles, west to Louisiana and southern Arkansas, 

 and as far north as Maryland. This enormous spread was speedily 

 effected by the droves of cattle and horses following the armies during 

 the late war. Greedily eaten by the animals, the seeds being voided 

 without being injured and readily germinating in the decaying drop- 

 pings, this annual was soon permanently established in the open 

 woods and pasture lands, over hill and lowland, throughout a vast 

 extent of country. The bitterweed (Ilelenium, tenuifolium), originally 

 from the sunny plains west of the Mississippi River south of the 



