PEDIGREE - CULTURE r q 



seed-pans, thus demonstrating the efficiency of the violet's 

 method of dissemination. As none of the cultures then in the 

 seed-pans were violets, no harm was done by this unexpected 

 accession of violet seeds, but it is plain that special precau- 

 tions would be necessary in the study of the violets by the 

 pedigree method, in order to preclude the possibility of con- 

 tamination with seeds of unknown parentage. 



In times of heavy winds it is usually impossible to close 

 ventilators so tightly or the house in general so hermetically 

 that no dust or other debris carried by the wind can find its 

 way through the crevices. Shortly after such a dust storm 

 two specimens of Erechtites and one of Oxalis were seen 

 to germinate in pans with which the usual precautions had 

 been taken. As fragments of corn-leaves and of the inflores- 

 cences of Panicnm capillare ( ?) had been found in the propa- 

 gating house after the storm, it was natural to surmise that 

 the several seeds which appeared where they did not belong 

 had entered in the same way. 



When plans are being laid for the prosecution of pedi- 

 gree cultures on a fairly comprehensive scale the adoption of 

 some system of labeling and note-keeping which shall be suf- 

 ficiently complete and yet fairly simple is imperative. As 

 the personal equation of the investigator is always an Import- 

 ant factor in the adoption of such a system, I do not present 

 the methods used by me as those which are likely to seem 

 ideal to all people, but there may be some suggestions at 

 least which will be of value to others, either as a good way 

 to do it or the way not to do It. 



■ As the number of pedigrees handled is large, the only 

 feasible system of designating them is one whose chief char- 

 acteristic is the Arabic numeral. I have developed a system 

 which in different phases uses both the Roman numerals and 

 the letters of the alphabet, but which uses the Arabic numer- 

 als alone for the permanent designation, or pedigree-number 

 proper. All Arabic numbers used refer to specific Individuals. 

 Roman numerals are used only in the garden to designate the 



