ORDERS, CLASSES, AND THEIR SUBDIVISIONS. 361 



great convenience, especially for those wliich are most natural and 

 definite. For some of these intermediate groups may be as dis- 

 tinctly marked as are those which we call genera or orders. 



704. The great advantages and proper use of this intermediate 

 grouping are, that it secures all the benefits of complete analysis 

 without undue multiplication of genera and orders, and that, by ex- 

 tending the scale, more grades of relationship may be noted, and the 

 whole expressed in our systems in truer perspective. Accordingly, 

 when groups of species below what we take for genera are recog- 

 nized, and found to be so well marked that by a httle lowering of 

 the scale they would be received as genera, they are denominated 

 Subgenera. If less definite, we term them merely Sections. For 

 example, Pyrus, the Pear genus, embraces Apples, Pears, Crab- 

 apples and the like ; and the Pear itself is the type or normal rep- 

 resentative. From this the Apple and the several species of Crab- 

 apple differ considerably, but not quite enough to warrant generic 

 separation : they are therefore recognized as forming a subgenus, 

 Mains, of tlie genus Pyrus. Again, the Bramble genus, Ruhus, com- 

 prises both Easpberries and Blackberries, which, although distin- 

 guished by everybody, are not so much or so definitely diflTerent from 

 each other as Apples and Crab-apples are from Pears ; so they are 

 ranked merely as sections of the Bramble genus. If we were to 

 receive all such particular groujps of species as genera, and give them 

 substantive names, as many naturalists are doing, the nicer grada- 

 tions of affinity would be disregarded, while genera would be reck- 

 oned by tens of thousands ; at length half our species would become 

 genera with substantive names, and the whole advantage of classifi- 

 cation and nomenclature would be lost. The proper discrimination 

 of genera is the real test of a naturalist. 



705. When groups intermediate between genera and orders are 

 admitted, they are generally denominated Tribes, and their divis- 

 ions, if any, Subtribes. But the highest divisions of orders, when 

 marked by characters of such importance that it might fairly be 

 questioned whether they ought not to be received as independent 

 orders, take the name of Suborders. For example, the great 

 Eose family, as we receive it, embraces three suborders ; one of 

 them represented by the Plum, Peach, Almond, &c. ; a second, by 

 the Pear, Quince, Hawthorn, and the like ; and the third, by the 

 Rose itself and its immediate relatives. Some botanists receive 

 these three as so many orders : we regard them as suborders, be- 



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