Hi The Rev. P. Keith on the Classification of Vegetables. . 



is merely their exogenous and endogenous characters re- 

 spectively. 



The division of the Dicotyledons we subdivide into Dichla- 

 mydeae and Monochlamydea^, terms invented by DeCandolle, 

 but not introducing any new princi[)le that was not already to 

 be found in the system, and in full and actual operation. For 

 although the terms were not there, the things signified by them 

 were there, and were made available to the purposes of ar- 

 rangement, though not designated by individual names. The 

 former term is equivalent to the double envelope of calyx and 

 corolla, and the latter to the single envelope or perianth. They 

 are all exogenous. 



The division of the Monocotyledons J ussieu did not subdi- 

 vide into any minor groups, and neither do we. We notice 

 merely the leading peculiarities of the perianth. They are all 

 endogenous. 



In the whole of the above divisions, or subdivisions, the 

 classes are uniformly founded on the mode of the insertion of 

 the stamens, as being hypogynous, perigynous, or epigynous. 

 For although a novice might fancy that the principle of ar- 

 rangement changes with the change of termination in the 

 names that have been imposed upon the classes, yet the more 

 experienced botanist knows that the origin of the stamens and 

 corolla is uniformly and universally the same, and that what- 

 ever is predicable of the one in that respect, is predicable also 

 of the other; and although the introduction of these distinc- 

 tions, at least in the circumscribing of classes, has been de- 

 nounced as being wholly and essentially artificial, as well as 

 utterly and absolutely extravagant, on the score of its exhi- 

 biting a want of due oeconomy in the husbanding of resources, 

 and an improvident expenditure of botanical ammunition that 

 might have been rendered available in the construction of 

 orders and of genera *, yet this want of due ceconomy is alto- 

 gether imaginary. There is an abundance of characters re- 

 maining for the constructing of orders and of genera, as result- 

 ing from other and important peculiarities discoverable in the 

 form, structure, or position of the stamens, pistils, ovary and 

 ovula, fruit, seed, embryo, or from additional and similar pecu- 

 liarities discoverable in other parts of the flower or plant. 

 Hence the distinctions founded on the mode of insertion, in- 

 stead of being an objection to the method of Jussieu, are only 

 a proof of its excellence, in the facility which they give to in- 

 vestigation and in their applicability to the whole of the grand 

 group of cotyledonous plants, whether dicotyledonous or mo- 



* Roscoe on Arrangements, Linn.'I'rans., vol. xi. part I. [Or Phil. Mag. 

 and Annab, N. S., vol. vii.] 



