SPECIAL MORPHOLOGY. 139 



cells capable of affecting the form of their development is, whether 

 these cells become at an early period, isolated and independent, 

 whether they remain for a longer period of time, till their sub- 

 sequent development, merely as parts of the parent organism, as 

 secondary cells within the parent cell. In the latter case the pro- 

 pagating cells are enclosed within a parent cell (sporangium), 

 while in the former they are contained free in a cavity of certain 

 portions of cellular tissue (sporocarp, anther cell) ; and, grounding 

 my division on these points, I divide plants into covered-spored 

 (Ajigiosporce) and naked-spored (GymnosporcB). 



The next difference to be considered affects the manner in which 

 the spores are developed, whether under the influence of other cells of 

 the parent plant or not. We find that this affords us another ground 

 of division for the Gymnosporce, for the propagating cell either 

 develops itself freely to a new asexual plant (Plant agamicce), 

 which, together with the Angiosporce, have been termed, since the 

 time of Linnasus, Cryptogams ; or it requires for its development to 

 be previously encased by, and brought under the material influence 

 of, certain cells of the parent plant (sexual plants (PL gamicce). 

 Finally, under this last head, we may admit another difference 

 between plants having no definite point of union for the sexes (PL 

 athalamiccs), where the two different kinds of cells, or cellular 

 masses, only combine subsequently to their separation from the 

 parent plant, and plants having a definite point of union for the 

 sexes (PL thalamica or Phanerogamce), where the propagating cell 

 is taken up at a definite part of the parent plant, and there deve- 

 loped for a time previous to its separation from it. 



My words would be most erroneously construed, were it supposed for 

 a moment that I was arbitrarily constructing a form of division, and 

 then arranging the plants in accordance with it. So far from this, it 

 has been my endeavour first to form the groups by a comparison of the 

 whole history of development, and then seek for a characteristic by 

 which to designate the groups thus found, On taking a general survey 

 of the whole vegetable kingdom, unbiassed by previously conceived 

 views, we should be inevitably led to separate the Alga, Lichens, and 

 Fungi from all other plants, and arrange them in one common group, but 

 it must be left to a subsequently acquired and a more extended know- 

 ledge of all plants to determine the strict confines and the combination 

 of characteristics appertaining to this group. It cannot, however, be 

 denied that an essential difference is manifested in the formative prin- 

 ciples of the already named lower groups, and the higher plants, which, 

 although apparent to every observer, science is not always able to cha- 

 racterise. Granting even that in the form of separate lateral parts, as, 

 for instance, in the so-called fronds of the Floridetz, an analogy may 

 really be found with the leaf-formation of higher plants, this would 

 only be an evidence of the deficient condition of our knowledge, but 

 could not efface the line of demarcation which has here evidently been 

 drawn by Nature. Nageli, in opposing my mode of division, has afforded 

 a most signal proof of the difficulty, to those who have once been led 

 astray in dogmatising, of extricating themselves, although with the best 



