379g Dr. A. Braun 07i the Vegetable IndividuaL 



of generation of animals, a twofold reproduction appears in 

 plants : sexual and non-sexual. Disregarding for the present 

 the various relations of alternation of generation among the 

 Cryptogamia, we find sexual reproduction (in animals by ferti- 

 lized ova, — in plants by fertilized seeds) always vested in the 

 generation which concludes the cycle of generations. That the 

 consideration of this generation as the concluding one is not 

 arbitrary, is shown by comparing it with the usual course of 

 the metamorphosis ; for the concluding generation is invested 

 with the concluding formations of the metamorphosis (flower 

 and fruit), in the same way in fact as in the animal the complete 

 development of the organs of generation occurs at the summit 

 of the individual metamorphosis. The preceding (preparatory) 

 generations, which Steenstrup calls '' nurses,^^ on the contrary 

 invariably produce their brood by non-sexual reproduction : in 

 the animal kingdom this takes place, now through germ-granules 

 which develope in the interior of the body (as the nurses of 

 Distoma), now by a process of division in the posterior part of 

 the body (the nurse of the Medicsa, the Tape-worm), or finally 

 by external, persistent or deciduous, shoot-formations {CoryrKE, 

 Campanularice, Sertularia, &c.). Among Phanerogamia the last 

 is the only kind occurring subservient to alternations of gene- 

 ration. 



In animals, as in plants, the number of the generations in 

 which the cycle of alternation of generation is completed, is for 

 the most part a determinate one. Medusa, SalpcB, Corynce, and 

 Tubularice conclude this cycle in the second generation : according 

 to Steenstrup's showing, Distoma pacificum has a trimembral 

 alternation of generation, and the family stock of Pennatula 

 seems also to be formed by a trimembral succession of shoots. 

 Campanularia has a quadrimembral cycle, in which however the 

 two first generations are of the same character. Among Sertu- 

 lari<je, cycles of still more numerous members appear to occur : 

 eight to ten generations form the annual cycle of generation of 



Joachim Jung's time, and was brought forward especially by Roeper and 

 appUed by him to classifying inflorescences. It is exemplified, in that place, 

 by creeping stems, upright root-stocks, and by bulbs ; and the section on 

 indeterminate stems is unluckily exemplified by wrong cases, viz. Scirpus 

 palustris. Primula officinalis, and Menyanthes, to which indeterminate 

 main-shoots are falsely ascribed. — Steenstrup also lays down an alter- 

 nation of generation in plants, in the concluding remarks in his work 

 quoted above, as well as in his later book, ' Ueber das Vorkoramen des 

 Ilermaphroditismus hi der Natur ' (On the Pha^nomenon of Hermaphro- 

 ditism in Nature), though in an entirely different manner from mine as 

 here given ; for he compares the single leaves of the plant with the indi- 

 vidual in animals, — a mode of viewing the subject in regard to which I 

 have already expressed my opinion in the Introduction. 



