NOTES ON RECENT RESEARCH. 



699 



white and red seed give rise to a spotted white and red in varying degrees 

 from minute specks to patches. 



Hybrids may produce seeds which take all their characters (colour, 

 shape, size, &c.) from one parent, and pods having the characters (colour, 

 shape, stringiness, &c.) of the other parent. 



A hybrid may closely resemble one parent in the habit of plant and 

 in all characters of pods, and the other parent in seed characters. 



" Mosaics " may also be formed of characters of one or both parents 

 united with the blended characters of both parents. 



There may be an entire return to one parent. Then, in the second 

 and third generation of a certain Bean hybrid, numerous individuals were 

 so nearly like the male parent, and several so nearly like the female, that 

 they could scarcely be distinguished from those races by any character of 

 plant, pod, flower, or seed. When hybrid forms of second and later 

 generations return to a parent race in any character, the reversion seems 

 to be in accord with no law unless there be a definite numerical relation, 

 not yet established, between the various hybrid types. 



The writer confirmed Mendel's law (in which dominant characters 

 are those which are transmitted entirely or almost unchanged, and 

 recessive, those which become latent in the first-generation forms, but 

 reappear in later generations). Thus, when semi- dwarf races were crossed 

 with dwarf races, the first generation were all semi-dwarf. The recessive 

 character (i.e. strictly dwarf plants) appeared in the second generation. 

 Similarly, when green-podded and yellow-podded races are crossed, the 

 green colour of the pod is dominant, occurring alone in the first genera- 

 tion, the recessive colour appearing, together with intermediate forms, in 

 the second and later generations. 



New or atavistic characters may appear, which neither parent race 

 possesses.- In ' Davis' x ' Blue Pod,' the dark blue-green colour of the pods 

 of the latter race is dominant in the first generation hybrid forms. On 

 this blue-green ground colour appear numerous spots and splashes of red. 



In the second-generation forms the recessive pod colour, yellow, 

 appears sometimes alone, but often nearly covered with red or purple 

 spots, which were prominent in the first generation. This coloration 

 likewise appears in hybrids of certain other races. 



An even more peculiar circumstance is the coloration of hybrid seeds 

 corresponding to that of the pods. In 1 Davis ' x 1 Blue Pod ' the ground 

 colour of the seeds of the first-generation hybrids is apparently a blend 

 of brown and white, but on this ground-colour are spots and stripes of 

 red which fade to bluish purple. 



As this yellow or brown colour striped or spotted with red or purple 

 is common in the seeds of several races of Beans, such as ' Horticultural,' 

 ; Dwarf Do.,' ' Gcddard,' &c, it seems, therefore, that such races as ' Davis ' 

 and ' Mohawk ' came originally either directly or indirectly from races 

 similar to the last-named. — G. H. 



Embryology of Juglans. 



Juglandaceae, Embryology of. By G. Karsten ("Ueber die 

 Entwicklung der weiblichen Bliithen bei einigen Juglandaceen," Flora, 

 90 : 316-333, pi. 12, 1902. Review by C. J. Chamberlain, Bot. Gaz. 



