Harper : Native weeds and their probable origin 349 



The plants of the various unnatural habitats created in the 

 manners above indicated may also be classified as follows : 



1. Species undoubtedly indigenous in our forests, which spring 

 up quickly in clearings and to a lesser extent in other unnatural 

 places, and tend to restore them to their original condition. 



2. " Fireweeds," or species especially characteristic of recently 

 burned woodlands, gradually disappearing with the process of re- 

 forestation. Some of them are herbs, some shrubs and some 

 trees. If reforestation is prevented, as in case B % some of the fire- 

 weeds are apt to remain and behave like ordinary roadside or 

 introduced weeds. There are probably hardly more than a score 

 of typical fireweeds in the northeastern states, but very little is 

 known as yet of their origin and history. Lists of such-plants for 

 various northeastern localities have been published as follows : 



Dawson, Am. Jour. Sci. II. 4: 164-166. 1847. (Nova 

 Scotia.) 



Thoreau, Maine Woods, appendix. (There are several editions, 

 so it is hardly worth while to give date and page.) 



Prentiss, Bull. Torrey Club 10: 44. 1883. (Adirondacks.) 

 Chickering, Bot. Gaz. 9: 193-194. 1884. (Maine.) 



Sargent, Tenth Census U. S. 9 : 492, 497, 502-503, 510, 558. 

 1884. 



Fernald, Trans. Mass. Hort. Soc. 1905: 11. 1905. 



Chittenden, U. S. Bureau Forestry Bull. 55: 21, 37-38, 50- 

 5'. 67-70. 1905. (New Hampshire.) 



3- Species native in naturally treeless or sparsely wooded dry 

 areas ln tne same general regions, and therefore well adapted to 

 SUch un natural habitats as those under the second head. The 

 naturally treeless areas of this part of the country, other than those 



he seacoast and high mountains, are very imperfectly uhder- 



00d - The principal ones seem to be the "sand-plains" of the 



e f elev ated parts of New England, and the " Hempstead Plains " 



of T -r 



on g Island, which resemble in aspect some of the western 



j" aines - Existing botanical literature gives very little information 



* °ut such places. Two lists of New England sand-plain plants 



i!» e PUblished in 1903 ; one by J. W. Blankinship (Rhodora 5 : 



(H 11 I2 ^ f ° r easlern Massachusetts, and one by W. E. Britton 



u 1. Torrey Club 30 : 581-585) for southern Connecticut. Dr. 



