16 LAWSON : EEVISION OF THE 



such as the present, that the iuformatiou thus brought together may be made available 

 for general use, and prove au incentive to resident botanists and students to continue 

 and extend their labours, and direct their energies to the observation and record of 

 facts bearing upon questions that still need elucidation. 



It is Aï'ery desirable that collectors should be particularly careful to note the precise 

 localities and dates of collection of their specimens. "Where names of places are apt to be 

 mistaken, the latitude and longitude should be noted as nearly as possible. Svich facts 

 form useful scientific data. The tendency has been, in our large country, especially in 

 published floras and lists, to omit special localities, and to indicate the general 

 geographical range, or supposed range, of the plants over wide areas, in such vague terms 

 as, "from Canada to the Pacific," " from the Atlantic through the wooded country to the 

 Rocky Mountains and British Columbia," " Newfoundland, Labrador and Hudson Bay," 

 etc. In working out the distribution of plants, it is not safe to tabulate as facts such 

 statements as these, because there may be reasonable suspicion either that, in dif&cult 

 families, more than one species is included in the range indicated, or that the statement 

 may be the result of a mental impression rather than of a sufficient number of actual 

 observations. When we have the specimens from definite localities before us, they 

 can be compared and identified, and the range of the plants may thus be ascertained with 

 definiteness on actual data. Oar aim should be to collect materials for a Canadian flora, 

 bearing in mind that, whilst a paucity of facts was some excuse in the early days 

 for A'agueuess of generalization, now, the more material we accumulate, the greater 

 opportunity there is for precision in oiir work. The many imperfections of this paper will 

 indicate how much room remains for work in the field, in the herbarium, and in the 

 library. Its special objects are : — 



1. To show what species of Pamunculaceœ have been ascertained to be certainly 

 inhabitants of the Dominion of Canada, and of adjoining tracts of country that, for 

 purposes of geographical botany, cannot well be disconnected, — citations being given of 

 the historical evidence for their occurrence in cases of plants not observed during recent 

 years. 



2. To correct the nomenclature so as to bring it in accord, as far as possible, with 

 that adopted by the most recent and trustworthy authorities in the standard works of other 

 countries. 



3. To present concise descriptions of the several species, so as to enable students to 

 identify them with certainty. 



4. To give the synonyms and references necessary for tracing the history of the 

 several plants throughout botanical literature back to the first scientific recognition of the 

 species, wherever this can b3 done without over-burdening the record. In a few cases, 

 pre-Linnœau citations are given where they tend to elucidate or illustrate the early 

 history or distribution of a species, or the origin of its specific name. 



5. To point out the geographical range of these plants over Canada, and other parts 

 of the Northern Hemisphere. 



6. To record their local distribution, that is their presence or absence from particular 

 localities, or occurrence or absence throughoiit larger districts of the several provinces. 



7. To suggest points for observation in regard to those species that appear io bo of 



