1(S4 PHVTOCiKAPHY, 



the science, because attention, when hmited to one object, ob- 

 serves much more and better than when it is divided. Yet 

 this very Umitation of attention may give occasion to a certain 

 subtlety, or to too keen a penetration into particulars, and 

 many examples might be cited to shew, that the founders of 

 monographs are particularly easy to be induced to admit 

 more species than nature warrants. 



256. 

 Monograplis should especially correct synonymes. It is 

 also very useful, when they present us with plates of new or 

 very difficult species. In this respect we can highly recom- 

 mend the labours of Jacquin respecting the Oxalidae and Sta^ 

 peliae, Schkuhr on Reeds, Brown on the Contortae and Pro- 

 teaceae, De Candolle and Pallas on the Astragalae, Lambert 

 on Pines, Dunal on the Solaneae and Anoneae, Lehman on 

 the Asperifoliae, Humboldt on the Melastomae, Cavanilles on 

 the Malvaceae, Biria on Ranunculi ; Lyngbye, Turner and 

 Dillwyn, on Algae ; Hed^vig, Schwagrichen, and Hooker, oa 

 Mosses, and of the last author on Jungermanniae. 





VII. On Floras, 



257- 

 J No branch of botanical literature is more useful, and at 

 the same time more neglected than this. The Flora of a 

 country or region should contain an exact account of all wild 

 plants within the limits of that country or region. For a be- 

 ginner, therefore, it is the first, and one of the most impor- 

 tant aids for obtaining botanical knowledge. Confined to a 

 certain circle, the compiler of a Flora can study the peculiari- 

 ties of the plants of his region with diligence, distinguish true 

 species from subspecies, point out transitions, correct in this 

 way many errors, and lay the foimdation for a more correct 

 knowledge of plants. But there are a multitude of Floras 

 which contain nothing but a catalogue of names of pretend- 

 ed native plants of their region, with transcribed specific cha- 



