BIOLOGY^ e;XPERIME;nTAL — DAVENPORT. 99 



cross- and self-fertilization. In the cross-fertilized series care is being 

 taken to introduce newly arisen mutants wherever possible. 



The second generation of hybrid beans is being harvested, and enough 

 have been examined to show that the latency of a mottled color pattern 

 and a pigment darkener in the white variety used in these crosses was 

 correctly assumed. This allowed the prediction that in the second gener- 

 ation between white and yellow beans, for instance, there would be 

 found some individuals which would produce only plain black beans, and 

 some only yellow mottled ones, though neither form probably occurred 

 in the recent ancestry on either side of the pedigree. The prediction 

 has been realized, but whether the proportions will approximate those 

 expected can be seen only when the investigation of the several thousand 

 hybrid individuals has been completed. In addition to these expected 

 results there are a few individuals which belong to none of the predicted 

 classes, and these may indicate the presence of other latent characters not 

 detected in the first generation because they were recessive. Owing to 

 the lack of facilities for guarding against cross-fertilization, this point 

 can not be satisfactorily determined. 



Besides these hybrid beans, the following hybrids have been under 

 observation during the year: Lychnis alba Mill, (purple X white and 

 reciprocal), Bschscholtzia rosea X maritima Hort., Bursa bursa-pastoris (L,.) 

 Britton (several elementary species). Bursa bursa-pastoris X heegeri and 

 reciprocal, Verbascum blattaria L. (white X yellow), Verbascuin thapsus 

 X blattaria, Helianthus annuus L. ("Russian" X Western native). With 

 exception of the last, the results of these hybridizations generally agree 

 with what might be expected upon the basis of certain theoretical con- 

 siderations. Arrangements have been made to continue these hybrid 

 combinations and in addition an apparently successful attempt has been 

 made to secure hybrid seeds of Lycopersicon lycopersicon (L.) Karst and 

 L. solanopsis White. 



From May 15 until July 15 I was absent from the Station for the pur- 

 pose of studying the valuable horticultural work of Mr. Luther Burbank. 

 Notwithstanding the devotion of those left in charge of the cultures dur- 

 ing this time, several of them suffered irreparable injury. The most 

 unfortunate of these involved the "pure line" beans, and as I am likely to 

 be absent for considerable intervals during the next several years, it 

 seems best to abandon this experiment until such time as satisfactory 

 conditions for control may be attainable. 



Most of the specimens collected during 1905 for the herbarium have 

 been mounted. These are distributed as follows : The flora of Cold 

 Spring Harbor, Long Island, 480 specimens ; pedigreed plants, 452 speci- 

 mens; seedling and juvenile forms, 12 specimens; abnormalities, 22 speci- 

 mens ; total, 966 specimens. 



