THE LYCOPODS (CLUBMOSSES) 



O 



a b d 



Fig- 249. Meiosis in Z^co/)o</zMm6'e/a^oL., permanent acetocarmine. a. Polar view of the first metaphase. 

 X 1000. Forexplanatory diagram see Fig. 250. b. Side view of the first anaphase showing numerous 

 lagging univalents, x 1000. c. Side view of the first metaphase showing pairs and lagging univalents. 

 X 500. d. Side view of the second anaphase showing lagging half-chromosomes derived from split 

 univalents, x 500. 



any stage, and, without accurate knowledge of 

 chromosome number, detailed analysis of meiosis 

 cannot be carried out. It is obvious that nothing 

 less than a prolonged special study and probably 

 the application of new technical methods will 

 be needed to break this deadlock, and only an 

 approximate result can be given here. Demon- 

 stration of the qualitative side of irregular 

 pairing is, however, not difficult. Fig. 249c 

 shows the first meiotic metaphase, at a low 

 magnification, in a squash preparation in which 

 a cloud of univalents are conspicuous objects. 

 Laggards at anaphase, i.e. the univalents which 

 are splitting, are equally conspicuous in Fig. 249 b, 

 and they appear again at the end of the second 

 meiotic division in Fig. 249 a'. A fuller demon- 

 stration of the qualitative side of pairing is 

 scarcely required, and it should perhaps also be 

 pointed out that these figures do not represent 

 one plant at one season but are from several 

 places in several years. Fig. 249/* being from a 

 Scotch plant in 1936, Fig. 249 c and d from a 

 Welsh plant in 1938 and Fig. 249 a from a Lake 

 District plant in 1944. Irregular pairing must, therefore, be recognized as a charac 

 teristic feature of Z-. Selago over much, though not necessarily all, of Great Britain. 





O 

 O 







to 

 o 



Z. Selago 

 Fig. 250. Explanatory diagram to Fig. 2495. 

 X 2000. Paired chromosomes in black, 

 univalents in outline. 



(] 



251 



