66 MORPHOLOGICAL DEVELOPMENT. 



the exogenous mode of growth, there always goes either a 

 dicotyledonous or polycotyledonous germination. Why la 

 this? Such correlations cannot be accidental — cannot be 

 meaningless. A true theory of the phaenogamic types, in 

 their origin and divergence, should account for the conned • 

 ion of these traits. Let us see whether the foregoing theory 

 does this. 



The higher plants, like the higher animals, bequeath to 

 their offspring more or less of nutriment and structure. 

 Superior organisms of either kingdom do not, as do all in- 

 ferior organisms, cast off their progeny in the shape of 

 minute portions of protoplasm, unorganized and without 

 stocks of material fit for them to organize ; but they either 

 deposit along with the germs they cast off, certain quantities 

 of albumenoid substance, fit for them to appropriate while 

 they develop themselves, or else they continue to supply such 

 substance while the germs partially-develop themselves before 

 their detachment. Among plants, this constitutes the dis- 

 tinction between seeds and spores. Every seed contains a 

 store of food to serve the young plant during the first stages 

 of its independent life ; and usually, too, before the seed is 

 detached, the young plant is so far advanced in structure, 

 that it bears to the attached stock of nutriment much the 

 same relation that the young fish bears to the appended yelk- 

 bag at the time of leaving the egg. Sometimes, indeed, the 

 development of chlorophyll gives the seed-leaves a bright 

 green, while the seed is still contained in the parent- 

 pod. This early organization of the phssno- 

 gam, must be supposed rudely to indicate the type out of 

 which the phaenogamic type arose. On the foregoing hypo- 

 thesis, the seed-leaves therefore represent the primordial 

 fronds — which, indeed, they simulate in their simple, cellular, 

 unveined structures. And the question here to be asked is — 

 do the different relations of the parts in young endogens and 

 exogens correspond with the different relations of the primor- 

 dial fronds, severally implied by the endogenous and the 



