The Rev. P, Keith Ofi the Classijication of Vegetables. 115 



nocotyledonoiis, dichlamydeoiis or monochlamydeous, polype" 

 talous, nionopetalous, or apetalous; so that by retaining the 

 terms and divisions of Jussieu, we are, as it were, always in 

 company with him, or meeting with him at every turn. Hence 

 also the plan of procedure and the inquiries to be made by the 

 student are always the same in all the divisions of the group. 

 Is the plant cotyledonous or acotyledonous ; is it dicotyledo- 

 nous or monocotyledonous ; is its floral envelope single or dou- 

 ble ; is the flower polypetalous, monopetalous, apetalous, or 

 anomalous; are the stamens hypogynous, perigynous, or epi- 

 gynous ? This analysis brings him down to the several classes 

 of the first grand group, which, from their number, are pre- 

 vented from being surcharged with too many tribes or families. 

 When botanists are prepared to introduce classes founded 

 upon the principle suggested by Dr. Brown in his Botany of 

 Congo and of Terra Australis, that is, the })rinciple of com- 

 bining into an a^jgregate group, to be called a class, such orders 

 as are very closely allied, not merely by a single trait, but by 

 the sum of their affinities, enabling us to dispense with the use 

 of empirical characters entirely, then it will be time enough 

 to discard the classes of Jussieu. The objections to which 

 they are liable apply with equal force to the divisions by which 

 they have been superseded in the works of the above systema- 

 tists; all of them being clogged with anomalies that will puz- 

 zle the learner and impede him in his career, let him embrace 

 what system he will. 



The second grand group Jussieu did not divide into any 

 minor groups, but introduced merely as a single class. Yet 

 there is an evident demand for such a division, both from the 

 number of species which the group contains and from the 

 peculiarities of structure which several of its tribes display. 

 We adopt a division founded upon anatomical principles, and 

 indicated by features sufficiently obvious, as well as designated 

 by terms which, though novel, are peculiarly appropriate, 

 namely, the Ductulosa;, or cellular plants with ducts, but with- 

 out spiral tubes, as it is said ; and the Eductulosce, or plants 

 wholly cellular; the former propagated, perhaps, by seeds, 

 the latter by gems or sporules. The above terms appear to 

 liavebeen originally introduced by Mr. Arnott, of Edinburgh, 

 and seem to us to be quite unexceptionable *. The groups 

 which they designate we would erect into classes, the number 

 being still 15; for though we have thus split one of Jussieu's 

 classes into two, for reasons that to us seem valid, we have else- 

 where run two of his classes into one — the Epicorollae synan- 

 theree, and Epicorollae corisantherae, lor reasons that seem 

 • Encyc. Brit., art. Botany. 

 Q2 



