LINDLEY'S NATURAL SYSTEM OF BOTANY. 7 



simple or forked ; in which respect they approach Endogens 

 on the one hand, and Acrogens on the other. And finally, 

 their vascular system is very imperfect compared with that 

 of other Exogens of an equal degree of development. 



"The other group, called Rkizanthm, is far less correctly 

 known, but it seems to stand as it were between Endogens 

 and Acrogens of the lowest grade ; agreeing with the latter 

 in the absence or very imperfect state of the vascular system, 

 in a general resemblance to Fungi, and in the apparent seeds 

 being mere masses of sporules ; but apparently according 

 with Endogens in the ternary number of their floral enve- 

 lopes, and in the presence of fully developed sexes. 



" Certainly there is no possibility of obtaining such im- 

 portant primary groups as these by any kind of artificial con- 

 trivance." (Preface, pp. x.-xii.) 



The grand natural divisions of the natural kingdom are, 

 therefore, perfectly obvious, and may be very clearly defined. 

 With our present knowledge of vegetable structure no great 

 difficulty is experienced in characterizing the orders of natu- 

 ral families, and all subordinate groups. The great desi- 

 deratum has ever been to effect such an arrangement of the 

 orders under the primary classes that each family should be 

 placed next to those which it most nearly resembles. This 

 might easily be accomplished, if the idea once so strongly in- 

 sisted upon by poets and metaphysicians, of a chain of beings, 

 a regular gradation, by a single series, from the most perfect 

 and complicated to the most simple forms of existence, had 

 any foundation in truth. On the contrary, nothing is more 

 evident than that almost every order, or other group, is 

 allied not merely to one or two, but often to several others, 

 which are sometimes widely separate from each other ; and, 

 indeed, these several points of resemblance, or affinity, are oc- 

 casionally of about equal importance. A truly natural lineal 

 arrangement is therefore impracticable, since by it only one 

 or two out of several points of agreement can be indicated. 

 As this method is, however, the only one that can be followed 

 in books, all that can be done is to arrange the orders in such 

 a manner as to offer the least possible interruption to their 



