September 30, 1910] 



SCIENCE 



421 



gain a clear idea of how far the species and 

 varieties of the one correspond with those 

 of the other, owing to the diversities of the 

 names employed. It would be a great boon 

 to others as well as to students were a full 

 synonymic list prepared to show clearly the 

 equivalence of the names where those for 

 the same species or variety differ in the 

 different lists and manuals. Probably in 

 time an agreement will be generally ar- 

 rived at regarding the names to be ac- 

 cepted, but that desirable consummation 

 seems hardlj^ yet in sight. Meantime the 

 most useful step seems to be to show in how 

 far there is agreement in fact under the 

 different names. 



Among the cryptogams certain groups 

 have fared better than the higher plants as 

 regards both their later treatment and 

 their more adequate illustration by modern 

 methods and standards. Several works of 

 great value have dealt with the mosses, the 

 latest being Braithwaite's "British Moss- 

 flora," completed in 1899. The Sphagna 

 were also treated by Braithwaite in 1880, 

 and are to be the subject of a monograph 

 in the Ray Society's series. The liver- 

 worts have been the subject also of several 

 monographs, of which Pearson's is the 

 fullest. 



Among the Thallophji;a certain groups 

 have been more satisfactorily treated than 

 others — e. g., the Discomycetes, the Ure- 

 dinete and Ustilagineaj, the jMyxomycetes 

 and certain others among the fungi, and 

 the Desmidiaeete among the algte; but the 

 Thallophyta as a whole are much in need 

 of thorough revision to place them on a 

 footing either satisfactory or comparable 

 to their treatment in other countries. 



Of the Thallophyta many more of the 

 smaller species will probably be discovered 

 within our islands when close search is 

 made, if we may judge by the much more 

 numerous forms already recorded in cer- 



tain groiips abroad, and which almost cer- 

 tainly exist here also; but among the 

 higher plants it is not likely that many 

 additional species will be discovered as 

 native, yet even among these some will 

 probably be found. It is, however, rather 

 in the direction of fuller investigation of 

 the distribution and tendencies to varia- 

 tion within our islands that results of in- 

 terest are likely to be obtained. 



The labors of H. C. "Watson gave a very 

 great stimulus to the study of the distribu- 

 tion of the flora in England and Scotland, 

 and the work he set on foot has been taken 

 up and much extended by numerous bot- 

 anists in all parts of the British Islands. 

 It is largely owing to such work and to the 

 critical study of the flora necessary for its 

 prosecution that so many additions have 

 been made to the forms previously known 

 as British. Many local works have been 

 issued in recent years, often on a very high 

 standard of excellence. Besides these 

 larger works scientific periodicals and 

 transactions of field clubs and other socie- 

 ties teem with records, some of them very 

 brief, while others are of such size and 

 compass that they might have been issued 

 as separate books. A few of both the 

 books and papers are little more than mere 

 lists of names of species and varieties ob- 

 served in a locality during a brief visit; 

 but usually there is an attempt at least to 

 distinguish the native or well-established 

 aliens from the mere casuals, if these are 

 mentioned at all. In respect of aliens or 

 plants that owe their presence in a district 

 to man's aid, intentional or invoh;ntary, 

 their treatment is on no settled basis. 

 Every flora admits without question spe- 

 cies that are certainly of alien origin, even 

 such weeds of cultivated ground as disap- 

 pear when cultivation is given up, as maj' 

 be verified in too many localities in some 

 parts of our country. Yet other species 



