22 II. OEDERS AND GENERA. 



youngest student of botany soon learns to distinguish 

 Ferns, Grasses, and Sedges from all other plants. The 

 Filices may be said to stand out more prominently in 

 such respects than the other two groups. The Gramina 

 and Cyperoides not only have much closer affinities with 

 each other, but may perhaps also be said to have closer 

 affinities with some other plants not included in either 

 order. The illustration sought by the names in that first 

 line would have been more perfect by substituting Palmi 

 in place of Cyperoides ; it being wished there to avoid the 

 misleading influence of a generic name, as if implying 

 that the plants are grouped together because all the rest 

 resemble some typical genus, as Cy penis or Car ex 

 (" Sedges.") 



In the second line we have three other well charac- 

 terised orders. Their included plants resemble each 

 other in several decided characters ; and they are also 

 distinguishable from all other plants by the same, or by 

 some of the same characters. They difi'er, however, from 

 the three first-named orders, by their connecting and 

 diagnostic characters being almost restricted to the inflo- 

 rescence and its parts ; not pervading the plant so gene- 

 rally as is the case with those of the three former orders. 



Of none of these six groups can it be properly said, 

 that they constitute orders of themselves because their 

 included genera imbricate around one central genus, on 

 the plan of which they are all formed, with gi-adually 

 increasing or varying divergencies. In looking at Asple- 

 niuvi, Osmunda, and Hymenophyllum, for instance, we see 

 wide differences between the genera of a very " natural " 

 group. And to those botanists who love to select typical 

 genera, and to fancy the rest arranged around them, those 

 differences should suggest several such types among Fili- 

 ces, rather than a single central tyj)e for all. So likewise 



