298 Marquette, 3Ianifestations of polarity in plant cells whicli usw. 



indications of spmdle formation are present, that is. diiring synapsis. 



During synapsis the chromatin collects at one side of the liucleus 

 and thus for the time being brings ab out a visible polar Organization 

 of the cell. In anhnal cells the chromatin aggregates on the side 

 of the nucleus next to the central body; according to Harper the 

 sanie is also true of Phyllactinia. 1 ) For the higher plante no 

 explanation has as yet been offered as to what determines at 

 wnich side of the nucleus the chromatin shall aggregate. That 

 the position of the synaptic mass is not determined by gravity is 

 seen at once by exaniining any spore sac whose spore-mother-cells 

 are in synapsis. 



The fact that a conspicuous polar Organization of the cells of 

 higher plants appears at or about at the time of synapsis. at a 

 time when the plant is returning to a one celled condition. suggests 

 that this may be a striking back to an ancestral condition. 



Further evidence must be had as to whether the bodies in 

 the cytoplasm described in any of the cases just mentioned bear 

 any such deflnite and constant relation to the formation and 

 Position of the spindle as do the polar strnctures in the vegetative 

 cells of Isoetes. The conditions described for Equisetum and Marsüia 

 during synapsis suggest the existence of a deflnite polar Organization 

 in the cells of these plants. and Strasburger's observations on 

 Anthoeeros and Fitting's on the macrospore-mother-cells of Isoetes 

 point to a similar condition in these cases also. It is highly 

 desirable that a re-investigation of the spore-mother cells as well 

 as the vegetative cells of Anthoeeros and likevrise of the epidermal 

 assimilatory cells of Selaginella be undertaken from this Standpoint. 



The large chromatophores which are usually found singly in 

 the resting cells -in the vascular cryptogams certainly require 

 further investigation. Usually the Chromat ophore in the higher 

 plants is a strueture of relatively small dimensions; the leucoplast 

 may become hugely distended by a storage starch gram but in so 

 doing becomes so thin and so closely pressed against the starch 

 that it is difficult to distinguish it at all. The suspicion arises 

 that possibly the struetures found in Selaginella and in the spore 

 mother cells of Anthoeeros are not chloroplasts at all but that the 

 chloroplasts lie inside of these struetures. close about the starch 

 grains. This. however. can only be determined by further investi- 

 gation. Jhere are undoubtedly points of resemblence between the 

 polar struetures of Isoetes and the bodies-described as chromato- 

 phores in Anthoeeros. Still, the polar struetures of Isoetes bear a 

 relation to the karyokinetic figure which has not been described 

 for chrouiatophores. so that to include these struetures under 

 chromatophores would. for the present at least by entirely un- 

 marranted. I have so far called them starch bodies, but this term 

 is not without objeetions since these struetures also appear entireiy 



3 ) Harper. R. A.: Sexual reproduetion and the Organization of the nucleus 

 in certain mildews. (Carnegie Inst. Wash. 1905. PI. IV figs. 43 — 45.) 



