NATURAL ARRANGEMENT. 



493 



Perhaps he ha« discovered that his plant belongs to Rubiftrea- ; he will then have learned that all vegetables 

 with op;xj6ite entire stipulate leaves, and a monuftetalous 8U|>erior curulla, are also Kubiaceous. If a fraKinent 

 of the leaves and Htein only of such a plant were afterwards sulunittL-d tu him for exaniinatioa, hi- would 

 recognise its attinities, and rememl>er that it was itubiaceous, and, being aware of that fact, he would be able 

 •afely to infer that its calyx and corolla would l)e of a particul.ir nature; that if the roots aflurded any color 

 for dying, it would l>e red ; that the niwiicinal pro|>ertie8 of the bark, if any, would be tonic, astringent, and 

 febrifugal ; and that its seetls would be of ihe same nature as those of coflee; and, finally, its geographical 

 position would Ik* tolerably certain to him. 



The principal dithculty which has to be encountered by the student of the Natural System of plants is caused 

 by the want of an intrtnluction to the subjwt, accompanied by the characters of the several orders; this is 

 indeed removed as far as the Kritish Flora is coiicerniHl by the publication of Mr. Lindley's SunopsU, in which 

 the essential characters of all the wild Howering plants of this country are stated and analyse«l ; but it still 

 exists with resjMnrt to the vegetable kingdom in general. It is obviously imi>ossible to overcome this difficulty 

 here; all that we can do is to jioint out the characters of the great ilivisions under which the orders are 

 arranged ; even this necessarily very imperfect mode of treating the subject will probably remove tome of the 

 inconvenience that is at present experienced. 



Plants considereil with reference to their general itructurc, are separated into two grand divisions called 



Celll'la'*rks and Vas(1'la"'rf.s. 



The Cellulares answer to the Linncan Cryntog&mia, and are also called Acotyledbneae ; the Vasculares 

 answer to the re.st of the Linnean system, which is sometimes calle<l rhanerogiinia and Cotylcili'inex. 



Cklli'I.a^rks, C'RVPT(K;A>iors, or Acotvleoonohs, plants are all, therefore, ditterent tenns denoting the same 

 combination of vegetables. The first term is here adopted in preference to the others as expressing the most 

 obvious character u|)on which the division depends, namely, the cellular, not vascular, structure of the plants 

 composing it. Cellular plants are formed entirely of cellular tissue {Jig. 1.), without spiral vessels ^ or in 



a. Longitudinal section of a stem. f, Cnutaceoui thallus of a lichen, with shield*. 



6, TransTiTse section of a stem. g, Funpi of thv hiehi-st dignity, 



c. Stem of s moss, with leAvcs and theca, or seed-case. A, i, Funci of the lowest ranlt. 



a. Leaf of a moss ma^ificd. k, Conft-rva ma^^fied. 



(, Leafy thallus of a lichen, with shields. 



more familiar terms by having no veins in their leaves if foliaceous, and not forming wood ; they also are 

 destitute of perfect flowers. The lower tribes, such as Fungi and .A'lgae, arc destitute ot leaves, and in some 

 points approach the animal kingdom so nearly as to be scarcely distinguishable. In the highest tribe. Ferns, 

 apparent veins arc fomicd in the leaves ; but as they are not supplictl with spiral vessels, they cannot 

 be considered more than analogous to the veins of other plants. Ferns, however, hold the intermediate station 

 between Ccllulkres and Vasculares, and arc chiefly retained among the former on account of their perfect 

 accordance in other respects. In the whole of Acotylcdons, it is unnecessary to examine the seed for the 

 purpose of determining whether it has one cotyledon, several cotyledons, or none, the structure of the perfect 

 plant giving the most obvious and satisfactory evidence. 



Vascula bes, Ph.snogamous, or Cotvledonous, plants, arc also separated into two great classes called 

 Endogenes or Monocotyledons, and Ex(figcnes or Dicotyledons, both which are distinguished as accurately 

 bv their obvious physical structure as they are by the minute ami obscure peculiarities of the seed. They are 

 aU formed with cellular tissue, woody fibre, and spiral vessels {Jig. 2.), and their leaves are traversed by veins; 

 the last character is sufficient for practical purposes, if it is remembered that they also bear perfect flowers, 



/, \'ertlcal sei tion of a Tasrulor stem. o, I^-af of a dicotyUtionoui plant, 



m, Woody libre, or elonKata>> cellul.u tissue. (>, Leaf of a nioiiorot} Icdonuiu plant. 



n, .Spir.il vi-ssfl 



