3 1 6 Sir as burger. —The Reduction of Chromosomes . 
sideration shows yet once more to how great an extent the 
advance of theoretical comprehension affects the correct 
apprehension of the problem to be solved, and how this correct 
apprehension may save a great deal of superfluous labour. 
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 
significance in that they usually isolate themselves from 
cohesion with other cells and become independent, although 
this independence is only of practical utility in the case of 
the products of their division, that is, of the spores. Hence 
the centre of gravity of the developmental processes which 
take place in both micro- and macro-sporangia 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 1 . 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 archesporium is not a matter to 
which importance should be attached. For the archesporium 
is merely the merismatic tissue from which the spore-mother- 
cells are derived, a tissue which is frequently, but by no 
means necessarily, differentiated from the surrounding tissues 
at an early stage ; so that its differentiation cannot be of 
fundamental importance. 
Vergl. Entwicklungsgeschichte der Pflanzenorgane, 1883, p. 284. 
