CLASSIFICATION. 



297 



Stems and leaves undistinguishable 

 Stems and leaves distinguishable 



Asexual, or Flower less Plants. 



rAlgales 

 I. Thallogens < Eungales 

 Ujichenales 



II. ACROGENS 



rivi uscaiea 

 < Lycopodalea 

 lEilicales 



Sexual, or Flowering Plants. 



Wood of stem youngest in centre ; 

 cotyledon single. 



Leaves parallel-veined, permanent ; 

 wood confused 



Leaves net-veined, deciduous ; 

 wood, when perennial, arranged 

 in a circle with a central pith 



Wood of stem youngest at circum- 

 ference, always concentric ; coty- 

 ledons two or more. 



Seeds quite naked 



fGhimales 

 Arales 

 Palm ales 

 Hydrales 

 Narcissales 

 Amomales 

 Orchidales 

 Xyridales 

 Juncales 

 Li Hales 



LAlismales 



DlCTYOGENS. 



III. Endogens 



IV. 



V. Gtmnogens. 



f Diclinous 



Seeds enclosed in seed-vessels 



VI. Eiogens 



{Amentales 

 Urtieales 

 Euphorbiales 



&c. &c. 

 rViolales 



Hypogynous {«& 



Perigynous 



L Epigynous 



*• &c. &c. 

 rEicoidales 

 J Daphnales 

 I Rosales 

 *- &c. &c. 

 fCampanales 

 J M.vrtales 

 I Caetales 

 L &c. &c. 



Here, linear arrangement has disappeared: there is a 

 breaking up into groups and sub-groups and sub-sub-groups, 

 which do not admit of being placed in serial order, but only 

 in divergent and re-divergent order. Were there space to 

 exhibit the way in which the Alliances are subdivided into 

 Orders, and these into Genera, and these into Species ; the 



the parts no longer needed, abort, and those parts develop which favour the 

 preservation of the race. Similarly in the Rhizogens, the abortive development 

 of the leaves, the absence of chlorophyll, and the imperfect supply of spiral 

 vessels, are changes towards a structure fit for a plant which lives on the juices 

 absorbed from another plant; while the rapid and great development of the 

 fructifying organs, are correlative changes advantageous to a plant, the seeds of 

 which have but small chances of rooting themselves. And just the same reason 

 that exists for the production of immensely numerous but extremely small eggs 

 by Entozoa, exists for the production by Rhizogens, of seeds that are great in 

 number and almost spore-like in size. 



