263 AN INTRODUCTION* 



of the science; and the same eagerness led them 

 also to set down as new genera what should have 

 been species only. This, evil was in some measure 

 unavoidable, while there were no fixed principles 

 for the regulation of the science in this respect. A 

 remedy to it was first attempted by Vaillant; after- 

 wards by Jussieu, Haller, Royenus, Gronovius, and 

 others ; and lastly by Linnaeus, whose aphorisms 

 have brought the v<ork much nearer to perfection. 

 Something indeed seems still wanting to complete 

 these doctrines ; but perhaps more is not to be ex- 

 pected till this branch of natural philosophy receives 

 further assistance from experiment. 



We shall treat in this chapter of those circum- 

 stances by which species are distinguished with 'cer- 

 tainty, reserving the varieties for the chapter following. 



The ROOT often affords a real specific difference*, 

 and is sometimes the chief distinction ; as in Scilla, 

 where the species are scarce to be distinguished, but 

 by the bulbs being tunicate, solid or squamose ; and 

 in Orchis, where the species are known by the roots 

 being fibrose, round or testiculate ; but as access can- 

 not always be conveniently had to this part of the 

 plant, it is better to fix the specific distinction on some 

 other circumstance, if the case will admit of it. 



The TRUNK often furnishes a sure mark of dis- 

 tinction. Thus in Hypericum j~, ConvallariaJ, and 



* In Fumaria bulbosa, the greater and less sorts with a 

 hollow root, and the greater and less sorts with a root not 

 hollow, appear by the whole habit of the plants to be varieties 

 only, as will be observed in the next chapter. 



f- Hypericum hirsutum (Lin. spec, plant 786) caule anci- 

 piti. Hypericum quadraugulum (Lin. spec, plant. 785.) 

 caule quadrangulo. 



J Convallaria polygonatum (Lin. spec, plant. 315.) caule 

 ancipiti. 



Convallaria multiflora (Lin, spec, plant. 315. caule teretu 



