No. 607] NUMBERING PLANTS IN PEDIGREE CULTURES 43 1 



different numbers as No. 10 flour corn and No. 5 flint 

 corn." Then the hybrids would be desi^ated, for 

 example: (10x5)-l, (10 X 5)-2, (5 X 10)-1, etc. If, 

 however, the individual plants are regularly indicated 

 in the series numbers, these numbers tend to become un- 

 wieldy, particularly if the Pj plants themselves have some- 

 what lengthy pedigrees. In cases where this objection 

 does not apply, and where Belling's method is inadequate, 

 Hayes and East'^ scheme has some advantage in the im- 

 mediate significance of the series numbers of hybrids. 



Of the systems described, Webber's seems most gen- 

 erally applicable to work with the higher plants, though 

 the others may be somewhat more convenient in certain 

 cases. I wish to present several additions to that system, 

 designed in part to provide for somatic variation and 

 polyembryony. 



First, capital letters may be used, as is often done, for 

 various special purposes. For instance, letters are some- 

 times added to distinguish particular types; Shull (1908, 

 p. 60), in describing his system of pedigree records, re- 

 stricts letters (aside from Roman numerals) to this use, 

 and Hayes and East (1915, p. 4) use them to designate 

 floury and flint-like types of maize kernel. When tem- 

 porary lot numbers are used, "L" prefixed to these num- 

 bers will distinguisli them f rom any others. Again, Arabic 

 numerals iircrcdod by "H" seem more convenient than 

 Roman numtM-als as used l)y Slmll (1908, p. 60) to desig- 

 nate rows in field cultures— giving, for instance, Rl, 3 

 (row 1, plant 3) for 1, 3, and R28, 26 for XXVIIl, 26. I 

 would suggest that capital letters, and capitals only, be 

 employed for such miscellaneous purposes. 



Second, small letters may ho used for the indication of 

 parts of iiidividuaN. ^vho\hrv tlu' parl^ rnnain attached 



"-51a" in a Citrus ixMligrc,. wi! Miid'h-atc a particular 



