Withthevarietiesofmanyplants，theadaptationtoclimateisoftenveryclose。Thusithasbeenprovedbyrepeatedtrials\"thatfewifanyoftheEnglishvarietiesofwheatareadaptedforcultivationinScotland\"（24/54。
’Gardener’sChronicle’1851page396。）;butthefailureinthiscaseisatfirstonlyinthequantity，thoughultimatelyinthequality，ofthegrainproduced。TheRev。M。J。Berkeleysowedwheat—seedfromIndia，andgot\"themostmeagreears，\"onlandwhichwouldcertainlyhaveyieldedagoodcropfromEnglishwheat。（24/55。Ibid1862page235。）Inthesecasesvarietieshavebeencarriedfromawarmertoacoolerclimate;inthereversecase，as\"whenwheatwasimporteddirectlyfromFranceintotheWestIndianIslands，itproducedeitherwhollybarrenspikesorfurnishedwithonlytwoorthreemiserableseeds，whileWestIndianseedbyitssideyieldedanenormousharvest。\"
（24/56。OntheauthorityofLabatquotedin’Gardener’sChronicle’1862page235。）Hereisanothercaseofcloseadaptationtoaslightlycoolerclimate;akindofwheatwhichinEnglandmaybeusedindifferentlyeitherasawinterorsummervariety，whensownunderthewarmerclimateofGrignan，inFrance，behavedexactlyasifithadbeenatruewinterwheat。（24/57。MM。EdwardsandColin’Annal。desSc。Nat。’2ndseriesBot。tome5page22。）
Botanistsbelievethatallthevarietiesofmaizebelongtothesamespecies;
andwehaveseenthatinNorthAmerica，inproceedingnorthward，thevarietiescultivatedineachzoneproducetheirflowersandripentheirseedwithinshorterandshorterperiods。Sothatthetall，slowlymaturingsouthernvarietiesdonotsucceedinNewEngland，andtheNewEnglishvarietiesdonotsucceedinCanada。Ihavenotmetwithanystatementthatthesouthernvarietiesareactuallyinjuredorkilledbyadegreeofcoldwhichthenorthernvarietiescanwithstandwithimpunity，thoughthisisprobable;buttheproductionofearlyfloweringandearlyseedingvarietiesdeservestobeconsideredasoneformofacclimatisation。Henceithasbeenfoundpossible，accordingtoKalm，tocultivatemaizefurtherandfurthernorthwardsinAmerica。InEurope，also，aswelearnfromtheevidencegivenbyAlph。DeCandolle，thecultureofmaizehasextendedsincetheendofthelastcenturythirtyleaguesnorthofitsformerboundary。（24/58。’Geograph。Bot。’page337。）OntheauthorityofLinnaeus（24/59。’SwedishActs’Englishtranslation1739—40volume1。Kalminhis’Travels’volume2page166givesananalogouscasewithcotton—plantsraisedinNewJerseyfromCarolinaseed。），Imayquoteananalogouscase，namely，thatinSwedentobaccoraisedfromhome—grownseedripensitsseedamonthsoonerandislessliabletomiscarrythanplantsraisedfromforeignseed。