364 Tricotylous Races. 



seedling will have two such divisions and so become a 

 tetracotyl or hemi-tetracotyl. If, for instance, 50 divi- 

 sions are distributed over 100 seedlings, with 200 cotyl- 

 edons, hov/ often may we expect a single plant to present 

 two such divisions? 



In the same way the expectation of pentacot3ds may 

 be calculated. Without going closely into this calcula- 

 tion, it is obvious that the proportion of tetracotyls will, 

 on the whole, increase with that of the tricotyls indepen- 

 dently of course of the nature of the species in question. 

 As a matter of fact we do not observe such an independ- 

 ence. Some species are relatively rare in tetracotyls 

 wdiilst others produce them more abundantly. Thus An- 

 tirrhinuin inajns never gave more than 1% to 2% of 

 tetracotyls (Fig. 63 D, p. 345), although the proportion 

 of tricotyls was as much as 79%. Oenothera hirtcUa, 

 Scrophularia nodosa, and Cannabis sativa are also poor 

 in tetracotyls. The latter produced only 1 to 3.5% of 

 them, even when the wdiole value amounted to 63% (in 

 20 individual records). On the other hand, other species, 

 or at any rate the races of them wdiich I observed, pro- 

 duced tetracotyls abundantl}^ 



I have grouped together w'ell over 100 separate rec- 

 ords from my cultures of 1894-1896, in wdiich the hemi- 

 tricotyls, tricotyls and tetracotyls w^ere recorded sep- 

 arately for each sowing, which almost always consisted 

 of about 300 seeds. From these I have especially cal- 

 culated, besides the percentage composition in split-leaved 

 seedlings, the proportion of these to the tetracotyls; and 

 I eive below^ the number of tetracotvls per 100 tricotvls 

 in the wn'der sense of that term. This proportion varied 

 in Amarantns speciosns, for 2-10% tricotyls, and in Can- 

 nabis safh'a for 6-52%, between 1 and 7%. In Mer- 



