w. i.a\viii:m:1'- halls. — tiik iMiiiiiiTANcr. di- mkasi i!i;\i!i.i' i'.mauactrus ok cotton. i.'i 



lime il is iioncrally concodcd lliat coKuii planls inlcrrross ri(>(|ur'nlly: tlio 

 Wdik of AllanJ in llie U. S. A. miglil be specially menlioned. 



rii(> acknowledgcmont of Ihc exislcnco of 5 to 10 pei' conl ol' viiinisin 

 belwccn plants of closely relaled vaiielies in field crop, is a sli-p in mlvanco. 

 sincc il implios 

 Ihc récognition of 

 expérimental ei- 

 rors of a serions 

 kind. Itdocsnot, 

 however, exliaiisl 

 even this sidc of 

 Ihesubject. Tlir 

 writer lias found 

 a far larger \alnc 

 for vicinisni on 

 Ihe breeding plot, 

 where plants of 

 Ihe most varic<l 

 gamelle constiln- 

 lion are grovving 

 inproximity ; herc 

 Ihc apparent error 

 has risen to 100 

 per cent, or — 

 makingallowanic 

 for the slronger 

 germinationofthe 

 vicinists — abont 

 25 per cent of vi- 

 cinistic embryos: 

 much variation in 

 this respect is 

 shown by dill'c- 



renl familics, and ^^ ** 



llierc would scen 



lo be a certain variation in snsceptibilily, similai- to that which plants show lo 

 certain parasitic fungi. The analogy between the pollen tnbc and the fungns 

 hypha was pointed out by the late Prof. II. Marshall ^^'a^d. 



Again, lliongh the amount of inter-Egyptian vicinism in l'icld nop in l'^gypt 

 amonnts to at least five per cent, yct Ihe vicinism between Kgyjtlians and the 

 weed « Hindi » (closely simiiar lu American Uplands), is very much less than 

 this, and hybrids of thèse Iwo are rclatively uncommon in the tield, Ihough 

 readily made artificially. Classifying thèse two groups of cotton as rejtuled 

 species, we thus find relative immimity of eithcr s]iecics IVom infection by 

 pollen of the othtT. 



Thèse points liave becn sulijected lo a prcliminary e.xaminalion by the 

 wriler, using a method of mixed-pollinalion. The resiilt of the tests indicates 

 that roughiy two per cent of vicinists (i.e., F,, plants) an* foi'med between 

 Egyptian and .\mericaii l'plands wlien Ijolh |)ollens arc prcseni in cqiial 



3 3 



