326 TAXONOMY. 



i 



<;:><). This is the common f mmc work of natural history classi- 

 fication. All plants and all animals belong to some species; 

 every species to some genus; every iienn-> to some order or 

 family; every order to some class; every class to one or the 

 other kingdom. 1 But this framework, although all that is re- 

 quisite in some parts of natural history, does not express all the 

 olervalile gradations of relationship among species. And even 

 gradations I >elow species ha\e sometimes to IK- classified. The 

 Aeries is capable of extension ; and extension is often requisite 

 on account of the large number of objects to be arranged, and 

 the various degrees of relationship which may come into view. 



(',.") 1. This is effected by the intercalation of intermediate 

 grades, to be introduced into the system only when there is 

 occasion for them. And in botany one or more grades superior 

 to the classes are needful ; for first and foremost is the great 

 division of all plants into a higher and a lower SERIES 2 (or sub- 

 kingdom), the I'li;enogainous and the Cryptogamous. 



652. The grades intercalated into the long-established sequence 

 of Class, Order, Genus, and Species, with new names, are mainly 

 *wo, Tribe and Cohort. 



653. Tribe has been for a generation or two thoroughly estab- 

 lished in both kingdoms, as a grade inferior to order and supe- 

 rior to genus. In botanical classification, much use is made of 

 this grade, genera being grouped into tribes. 



654. Cohort (Lat. Cohors) is of more recent introduction, at 

 least in Botam r , but is becoming established for a grade next 

 above that of order. Orders are grouped into cohorts. Lindley 

 hit upon a good English name for this grade, that of Alliance. 

 But this word has no available Latin equivalent: while cohort 

 takes equally well a Latin or an English form. 



i'>~i~>. Finally, each grade is capable of being doubled by the 

 recognition of one like it and immediately subordinate to it, and 

 with designation directly expressive of the subordination. For 



1 Nut reeogni/ing TliBckel's third kingdom of Protista, consisting of those 

 Imvrst forms of bring from which the animal and vrgrtalilr kingdoms 

 emerge. 



- Answering to the French Embranchement in zoology. For this it is pro- 

 posed to use the won! [ >'irhi<i (IHrixin) : see Laws of Botanical Nomencla- 

 ture ndmited by the International Botanical Congress held at Paris in 

 August, isdT ; to!_ r et her with a Historical Introduction and a Commentary, by 

 Alph. DcCandnlle, Fn^lish translation, London, 18(18; the original French 

 edition. Paris. 1SC7. Perhaps no better name can be found; but the elder 

 DeCandolle brought ftin'sio into common use for a grade subordinate to 

 tribe. F.ndlicher employed the term Regio. We have used Series, and 

 much prefer it 



