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phosis of the organs of plants can only be advanced by means 

 of observation. The history of the development, which must 

 be pursued from the earliest appearance, alone gives the cor- 

 rect solution respecting the destination of the various organs 

 of plants. 



The embryo in the seeds of plants, says M. Schleiden, ori- 

 ginally consists of an axile formation, which is closed superi- 

 orly but is not limited inferiorly ; the upper end expands in a 

 globular form, and from the sides of this globe the cotyledons 

 proceed, while the apex developes to form a bud. What takes 

 place in the embryo is again repeated in the growth of the 

 leaves on the subsequent stem, and consequently this cannot 

 consist of adherent leaf-stalks. M. Schleiden is of opinion 

 that in investigating the laws of position of the leaves we must 

 set out from originally opposite ones, as exhibited in the coty- 

 ledons. That calyx and corolla are to be considered as folia- 

 ceous organs is generally admitted, and M. Schleiden also ob- 

 served that the monopetalous calices and corollae are in their 

 early stage noncohering, as also that every flower has in its in- 

 cipient development a regular construction. The grasses are 

 mentioned as a highly remarkable example, in which the organs 

 of fructification have, as is well known, been variously ex- 

 plained, since here non-cotemporaneous development, adhe- 

 sion and suppression of individual parts, quite disfigure the 

 original regularity. Nor can any longer doubt exist respecting 

 the formation and signification of the stamens ; they are mo- 

 dified leaves in whose diachyma four (this is the general law) 

 cavities occur filled with pollen. Sometimes, though rarely, 

 the original middle lamella is not developed, and then the di- 

 vision into two lateral cells does not exist, but it then appears 

 bilocular. 



The formation of the pollen takes place in these cavities, 

 and in fact in the interior of primitive cells, in which proba- 

 bly for the most part four other cells are formed, in which the 

 single grains of pollen are produced. The quadruple number 

 is here the more general rule, yet, at times, as in Podostemon 

 ceratophyllum, there are only two grains of pollen found in 

 the large primitive cell. After the development of the pollen 

 the re-absorption of the primitive cells takes place, which in 

 some plants is effected entirely, in others less completely. 

 Nay, even with respect to the re-absorption of the large and 



