OF THE NATURAL ARRANGEMENT. Ill 



compare together and to distinguish. Whilst in this plan 

 we are confined by no method, we actually exhaust the re- 

 gion of possibilities, at the same time that we are studying 

 realities. Yet the circumstantiality and discursiveness of 

 these investigations are objections to the plan. No person lias 

 pursued it with more ability and success, in later times, than 

 Gaudin, in his Agrostohgia Helvetica, 1811. When, for 

 example, he wishes to teach us to distinguish the species of 

 Festuca, he first attends to the leaves, whether they are all 

 bristly, or whether the stalk-leaves be smooth ; then to the in- 

 tegument of the leaves, whether it be very short and truncated, 

 or very prominent ; next he attends to the spicula?, whether 

 they be oval or oblong, with a^vns or without them ; lastly, to 

 the awns themselves, whether they be as long as the spicidae, 

 or longer. 



For facilitating the diagnosis of individual species, the ana^ 

 lytical method is very useful ; but it requires too great an ex- 

 pence of time and labour to be used on every occasion in the 

 examination of plants. If, for instance, we wish to deter- 

 mine a Myrtle, we must first ask whether it belongs to the 

 division of plants with distinct sexual parts, or with those that 

 are hidden ; whether it be monoclinous or diclinous ; whe- 

 ther the sexual parts stand free or are united, to what organ 

 they are fixed, in what number they are present; whether 

 the seeds have albumen or not ; what situation the plumula 

 has with respect to the umbilicus and the cotyledons ; still 

 further, how the corolla is fashioned, how its estivation takes 

 place, whether the plant be a tree or an herb, what is the 

 formation of its leaves, and their situation in the buds, and 

 so forth. The answer to these questions depends on inqui- 

 ries, which always lead to certain, comprehensive, and useful 

 knowledge. They are also applicable to every system, but 

 for elementary instruction they are in every case too dis- 

 cursive. 



