CLASSIFICATION OF PLANTS. 991 



Genera secundum Ordmes Naturales digesta, eonimque differentiae et affiaitatea tabulis 

 diagnosticis expositse,' of which the following is a sketch : — 



A. Vasculaees. 



I. Dicotyledons. 



t Diplochlamydal. ) 



* Dialypetalons or Polypetalous. 



1. Thalamifloral (13 classes and 75 orders). 



2. Calycifloral (7 classes and 36 orders). 

 ** Monopetalous. 



a. Fruit inferior (3 classes and 13 orders). 

 /?. Fruit superior (8 classes and 49 orders), 

 tt Monochlamydal (7 classes and 64 orders). 



II. Monocotyledons (9 classes and 38 orders). 



B. Cbllulaees. 



III. AcOTTLBDONS (not described). 



This is much the same as the CandoUean arrangement ; the principal defects are : the 

 not recognizing the Gymnospermous division except as a division of Monochlamyds ; 

 and the retention of Lindley's faulty class of Rhizanths, which he farther places in Mono- 

 cotyledons. 



Adrien de Jussieu, Professor of Plant Culture at the Jardin des Plantes, son of Antoine- 

 Laurent, published in 1844 a modification of his father's arrangement, which is much used 

 in France, and is farther modified at p. 167 of this work. It regards the Gymnosperms as 

 a primary division of Dicotyledons, retains Rhizanths, classing them under Angiospermous 

 Dicotyledons, and brings the Diclines into juxtaposition with the Apetalse. 



Various other methods and systems have been proposed, most of which have never 

 been adopted by any one, and but few even by their proposers. None are of sufficient 

 importance to merit discussion here, though many good suggestions may be obtained 

 from their study. A list of them will be found in Lindley's ' Vegetable Kingdom,' 2nd edit., 

 published in 1847. 



A review of the foregoing schemes establishes the following propositions : — The 

 primary division of Vegetables is into Phaanogams and Cryptogams ; — that of Phsenogams 

 is into Dicotyledons and Monocotyledons ; — that of Dicotyledons is into Angiosperms and 

 Gymnosperms ; — that of Cryptogams is into Acrogens (for the most part vascular) and Thal- 

 logens (or purely cellular) ; also that the perianth must be resorted to for the purpose of 

 further grouping the Angiospermous Dicotyledons and the Monocotyledons. Beyond this, 

 except in the case of Cryptogams, it is difficult to establish any subdivisions higher than 

 that of Orders ; and of the Phsenogamous Orders themselves, it is astonishing how few are 

 absolutely limited. Of the 278 described in this work, excluding those containing only one 

 or two genera, a large proportion either are connected with one or more others by a series 

 of intermediate genei-a, or contain genera which present so many of the characters of other 

 Orders that it is altogether uncertain in which of them they should be placed : such do 

 not oblige us to unite the Orders between which they oscillate, but they render vague the 

 definition of that in which tbey are placed. With Cryptogams the case is very diflFerent ; 

 the principal Orders and higher groups of the Vascular division are comparatively well- 

 limited and it is only the Cellular whose ordinal limits are undefined. And not only (are 

 the Orders of Cryptogams far better limited, but many of them are far more comprehen- 



