SIGNIFICANCE OF CONJUGATE NUCLEI 



273 



basidium. Finally, a nucleus creeps from the basidium-body 

 through a sterigma into each spore, so that, at last, each spore 



AB cd> Ai aB 



ABAB ab ah 



Ai Ai clB aB 



Fig. 



144. — Copriniis lagopus. Diagram showing the arrangement of the spores of 

 diverse sex on thirty-one ba^idia seen from above. The four kinds of spores 

 (AB), {ab), (Ab), and (aB) can be arranged on a basidium in seven different 

 ways, all of \.hich are here represented. The inner circle in each spore repre- 

 sents a nucleus, and the symbols within a pair of sex factors. The number in 

 the centre of each basidium gives the actual number of basidia (of the thirty-one 

 investigated) found with the arrangement of spores represented. The first 

 column shows the two possible arrangements when there are two (AB) and 

 two (ab) spores on a basidium ; the second column the three possible arrange- 

 ments when there are four khids of spores, (AB), (ab), (Ab), and (aB), on a 

 basidium ; and the third column the two possible arrangements when there 

 are two (.46) and two (aB) spores on a basidium. Investigations carried out 

 by Dorothy Newton. Drawn by the author and Dorothy Newton. 



becomes a haploid cell (Fig. 143, No. 5). In Coprinus lagopus,'^ as 

 shown in Fig. 144, there are three kinds of basidia . (1) basidia 

 which bear two (AB) and two (ab) spores ; (2) basidia which bear 



' Dorothy E. Newton, " The Distribution of Spores of Diverse Sex on the 

 Hymenium of Coprinus lagopus,'' Annals of Botany, vol. xl, 1926, j^p. 891-917. 



VOL. IV. 



