THE MICROSPORANGIUM 43 



as ushering in the gametophyte was first urged by Stras- 

 burger, 12 whose paper closes as follows: 



" The reduction in number of the chromosomes takes place, 

 among the higher plants, in the mother-cells of the spores, and 

 it is consequently these which must be regarded as the first 

 term of the new generation. They assert this their true sig- 

 nificance in that thev usually isolate themselves from cohesion 

 with other cells and become independent, although this inde- 

 pendence is only of practical utility in the case of the products 

 of their division — that is, of the spores. Hence the center of 

 gravity of the developmental processes which take place in both 

 micro- and macrosporangia of Cryptogams and Phanerogams 

 does not lie in those cells, cell-rows, or cell-aggregates which 

 give rise to the sporogenous tissue and have been designated 

 ' archesporium ' by Goebel. The archesporium still belongs 

 to the sexually developed asexual generation; it is only the 

 spore mother-cells which initiate the new sexual generation ; 

 consequently the presence or absence of a well-defined arche- 

 sporium is not a matter to which importance should be 

 attached." 



LITERATURE CITED 



1. Purkixje. J. E. De cellulis antherarum fibrosis nee non de gra- 



nopnm pollinarium formis commentatio phytotomica. Yrati- 

 slaviae. 1830. 



2. Nageli, C. Zur Entwicklungsgesehichte des Pollens. Zurich. 



1842. 



3. Hofmeister. W. Xeuere Beobachtungen fiber Enibryobildung 



der Phanerogamen. Jahrb. Wiss. Bot. 1 : 82-188. pis. 7-10. 

 1858. 



4. Rosaxoff. S. Zur Kermtniss des Baues mid der Entwicklungs- 



gesehiehte des Pollens der Mimoseae. Jahrb. Wiss. Bot. 4: 441- 

 450. pis. 31-32. 1865. 



5. Rohrbach. P. Die Samenknospe der Typhaceen. Bot. Zeit. 27 : 



479-480. 1869. 



6. Kauffmaxx. N. Ueber die mannlichen Blfithe von Casnarina 



quadrivalvis. Bull. Soc. Nat. Moscou 41 : 374-382. 1869. 



7. MAGNUS. P. Zur Morphologie der Gattung Xaias L. Bot. Zeit. 



27: 7('i9-773. 1869. Also Beitrii<re zur Kenntniss der Gattung 

 Xaias L. Berlin. 1870. 



8. Warmixg. E. Untersuchungen fiber pollenbildende Pliyllome 



und Kaulome. Hansteins Bot. Abhandl. 2: 1-90. pis. 1-6. 

 1873. 



