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。
WiththeVine，differentlyfromthemaize，thelineofpracticalculturehasretreatedalittlesouthwardsincethemiddleages（24/60。DeCandolle’Geograph。Bot。’page339。）;butthisseemsduetocommercebeingnoweasier，sothatitisbettertoimportwinefromthesouththantomakeitinnortherndistricts。Neverthelessthefactofthevinenothavingspreadnorthwardshowsthatacclimatisationhasmadenoprogressduringseveralcenturies。Thereis，however，amarkeddifferenceintheconstitutionoftheseveralvarieties，——
somebeinghardy，whilstothers，likethemuscatofAlexandria，requireaveryhightemperaturetocometoperfection。AccordingtoLabat（24/61。’Gardener’sChronicle’1862page235。），vinestakenfromFrancetotheWestIndiessucceedwithextremedifficulty，whilstthoseimportedfromMadeiraortheCanaryIslandsthriveadmirably。
GallesiogivesacuriousaccountofthenaturalisationoftheOrangeinItaly。
Duringmanycenturiesthesweetorangewaspropagatedexclusivelybygrafts，andsooftensufferedfromfrosts，thatitrequiredprotection。Aftertheseverefrostof1709，andmoreespeciallyafterthatof1763，somanytreesweredestroyed，thatseedlingsfromthesweetorangewereraised，and，tothesurpriseoftheinhabitants，theirfruitwasfoundtobesweet。Thetreesthusraisedwerelarger，moreproductive，andhardierthantheoldkinds;andseedlingsarenowcontinuallyraised。HenceGallesioconcludesthatmuchmorewaseffectedforthenaturalisationoftheorangeinItalybytheaccidentalproductionofnewkindsduringaperiodofaboutsixtyyears，thanhadbeeneffectedbygraftingoldvarietiesduringmanyages。（24/62。Gallesio’TeoriadellaRiproduzioneVeg。’1816page125;and’TraiteduCitrus’1811page359。）
ImayaddthatRisso（24/63。’Essaisurl’Hist。desOrangers’1813page20
etc。）describessomePortuguesevarietiesoftheorangeasextremelysensitivetocold，andasmuchtendererthancertainothervarieties。
ThepeachwasknowntoTheophrastus，322B。C。（24/64。Alph。deCandolle’Geograph。Bot。’page882。）AccordingtotheauthoritiesquotedbyDr。F。
Rolle（24/65。’Ch。Darwin’sLehrevonderEntstehung’etc。1862s。87。），itwastenderwhenfirstintroducedintoGreece，andevenintheislandofRhodesonlyoccasionallyborefruit。Ifthisbecorrect，thepeach，inspreadingduringthelasttwothousandyearsoverthemiddlepartsofEurope，musthavebecomemuchhardier。Atthepresentdaydifferentvarietiesdiffermuchinhardiness:someFrenchvarietieswillnotsucceedinEngland;andnearParis，thePaviedeBonneuildoesnotripenitsfruittillverylateintheseason，evenwhengrownonawall;"itis，therefore，onlyfitforaveryhotsouthernclimate。"（24/66。Decaisnequotedin’Gardener’sChronicle’1865page271。）
Iwillbrieflygiveafewothercases。AvarietyofMagnoliagrandiflora，raisedbyM。Roy，withstandsatemperatureseveraldegreeslowerthanthatwhichanyothervarietycanresist。Withcamelliasthereismuchdifferenceinhardiness。OneparticularvarietyoftheNoisetterosewithstoodtheseverefrostof1860"untouchedandhaleamidstauniversaldestructionofotherNoisettes。"InNewYorkthe"Irishyewisquitehardy，butthecommonyewisliabletobecutdown。"Imayaddthattherearevarietiesofthesweetpotato（Convolvulusbatatas）whicharesuitedforwarmer，aswellasforcolder，climates。（24/67。ForthemagnoliaseeLoudon’s’Gardener’sMag。’volume13
1837page21。Forcamelliasandrosessee’Gardener’sChronicle’1860page384。Fortheyew’JournalofHort。’March3，1863p174。ForsweetpotatoesseeCol。vonSieboldin’Gardener’sChronicle’1855page822。）]
Theplantsasyetmentionedhavebeenfoundcapableofresistinganunusualdegreeofcoldorheat，whenfullygrown。Thefollowingcasesrefertoplantswhilstyoung。InalargebedofyoungAraucariasofthesameage，growingclosetogetherandequallyexposed，itwasobserved（24/68。TheEditor’Gardener’sChronicle’1861page239。），aftertheunusuallyseverewinterof1860—61，that，"inthemidstofthedying，numerousindividualsremainedonwhichthefrosthadabsolutelymadenokindofimpression。"Dr。Lindley，afteralludingtothisandothersimilarcases，remarks，"Amongthelessonswhichthelateformidablewinterhastaughtus，isthat，evenintheirpowerofresistingcold，individualsofthesamespeciesofplantsareremarkablydifferent。"NearSalisbury，therewasasharpfrostonthenightofMay24，1836，andalltheFrenchbeans（Phaseolusvulgaris）inabedwerekilledexceptaboutoneinthirty，whichcompletelyescaped。（24/69。Loudon’s’Gardener’sMag。’volume121836page378。）Onthesamedayofthemonth，butintheyear1864，therewasaseverefrostinKent，andtworowsofscarlet—
runners（P。multiflorus）inmygarden，containing390plantsofthesameageandequallyexposed，wereallblackenedandkilledexceptaboutadozenplants。Inanadjoiningrowof"Fulmer’sdwarfbean"（P。vulgaris），onesingleplantescaped。Astillmoreseverefrostoccurredfourdaysafterwards，andofthedozenplantswhichhadpreviouslyescapedonlythreesurvived;thesewerenottallerormorevigorousthantheotheryoungplants，buttheyescapedcompletely，withnoteventhetipsoftheirleavesbrowned。Itwasimpossibletobeholdthesethreeplants，withtheirblackened，withered，anddeadbrethrenallaround，andnotseeataglancethattheydifferedwidelyinconstitutionalpowerofresistingfrost。
Thisworkisnottheproperplacetoshowthatwildplantsofthesamespecies，naturallygrowingatdifferentaltitudesorunderdifferentlatitudes，becometoacertainextentacclimatised，asisprovedbythedifferentbehaviouroftheirseedlingswhenraisedinanothercountry。Inmy’OriginofSpecies’Ihavealludedtosomecases，andIcouldaddmanyothers。
Oneinstancemustsuffice:Mr。Grigor，ofForres（24/70。’Gardener’sChronicle’1865page699。Mr。G。Mawgives（’Gardener’sChronicle’1870page895）anumberofstrikingcases;hebroughthomefromsouthernSpainandnorthernAfricaseveralplants，whichhecultivatedinEnglandalongsidespecimensfromnortherndistricts;andhefoundagreatdifferencenotonlyintheirhardinessduringthewinter，butinthebehaviourofsomeofthemduringthesummer。），statesthatseedlingsoftheScotchfir（Pinussylvestris），raisedfromseedfromtheContinentandfromtheforestsofScotland，differmuch。"Thedifferenceisperceptibleinone—year—old，andmoresointwo—year—
oldseedlings;buttheeffectsofthewinteronthesecondyear’sgrowthalmostuniformlymakethosefromtheContinentquitebrown，andsodamaged，thatbythemonthofMarchtheyarequiteunsaleable，whiletheplantsfromthenativeScotchpine，underthesametreatment，andstandingalongside，althoughconsiderablyshorter，areratherstouterandquitegreen，sothatthebedsoftheonecanbeknownfromtheotherwhenseenfromthedistanceofamile。"Closelysimilarfactshavebeenobservedwithseedlinglarches。
[HardyvarietieswouldalonebevaluedornoticedinEurope;whilsttendervarieties，requiringmorewarmth，wouldgenerallybeneglected;butsuchoccasionallyarise。ThusLoudon（24/71。’ArboretumetFruticetum’volume3
page1376。）describesaCornishvarietyoftheelmwhichisalmostanevergreen，andofwhichtheshootsareoftenkilledbytheautumnalfrosts，sothatitstimberisoflittlevalue。Horticulturistsknowthatsomevarietiesaremuchmoretenderthanothers:thusallthevarietiesofthebroccoliaremoretenderthancabbages;butthereismuchdifferenceinthisrespectinthesub—varietiesofthebroccoli;thepinkandpurplekindsarealittlehardierthanthewhiteCapebroccoli，"buttheyarenottobedependedonafterthethermometerfallsbelow24degFahr。;"theWalcherenbroccoliislesstenderthantheCape，andthereareseveralvarietieswhichwillstandmuchseverercoldthantheWalcheren。（24/72。Mr。Robsonin’JournalofHorticulture’1861
page23。）CauliflowersseedmorefreelyinIndiathancabbages。（24/73。Dr。
Bonavia’ReportoftheAgri。—Hort。Soc。ofOudh’1866。）Togiveoneinstancewithflowers:elevenplantsraisedfromahollyhock，calledtheQueenoftheWhites（24/74。’CottageGardener’1860April24page57。）werefoundtobemuchmoretenderthanvariousotherseedlings。Itmaybepresumedthatalltendervarietieswouldsucceedbetterunderaclimatewarmerthanours。Withfruit—trees，itiswellknownthatcertainvarieties，forinstanceofthepeach，standforcinginahot—housebetterthanothers;andthisshowseitherpliabilityoforganisationorsomeconstitutionaldifference。Thesameindividualcherry—tree，whenforced，hasbeenobservedduringsuccessiveyearsgraduallytochangeitsperiodofvegetation。（24/75。’Gardener’sChronicle’
1841page291。）Fewpelargoniumscanresisttheheatofastove，butAlbaMultiflorawill，asamostskilfulgardenerasserts，"standpine—appletopandbottomheatthewholewinter;withoutlookinganymoredrawnthanifithadstoodinacommongreenhouse;andBlancheFleurseemsasifithadbeenmadeonpurposeforgrowinginwinter，likemanybulbs，andtorestallsummer。"
（24/76。Mr。Beatonin’CottageGardener’March20，1860page377。QueenMabwillalsostandstoveheat。See’Gardener’sChronicle’1845page226。）TherecanhardlybeadoubtthattheAlbaMultiflorapelargoniummusthaveawidelydifferentconstitutionfromthatofmostothervarietiesofthisplant;itwouldprobablywithstandevenanequatorialclimate。
WehaveseenthataccordingtoLabatthevineandwheatrequireacclimatisationinordertosucceedintheWestIndies。SimilarfactshavebeenobservedatMadras:"twoparcelsofmignonette—seed，onedirectfromEurope，theothersavedatBangalore（ofwhichthemeantemperatureismuchbelowthatofMadras），weresownatthesametime:theybothvegetatedequallyfavourably，buttheformeralldiedoffafewdaysaftertheyappearedaboveground;thelatterstillsurvive，andarevigorous，healthyplants。""Soagain，turnipandcarrotseedsavedatHyderabadarefoundtoanswerbetteratMadrasthanseedfromEuropeorfromtheCapeofGoodHope。"（24/77。
’Gardener’sChronicle’1841page439。）Mr。J。ScottoftheCalcuttaBotanicGardens，informsmethatseedsofthesweet—pea（Lathyrusodoratus）importedfromEnglandproduceplants，withthick，rigidstemsandsmallleaves，whichrarelyblossomandneveryieldseed;plantsraisedfromFrenchseedblossomsparingly，butalltheflowersaresterile;ontheotherhand，plantsraisedfromsweet—peasgrownnearDarjeelinginUpperIndia，butoriginallyderivedfromEngland，canbesuccessfullycultivatedontheplainsofIndia;fortheyflowerandseedprofusely，andtheirstemsarelaxandscandent。Insomeoftheforegoingcases，asDr。Hookerhasremarkedtome，thegreatersuccessmayperhapsbeattributedtotheseedshavingbeenmorefullyripenedunderamorefavourableclimate;butthisviewcanhardlybeextendedtosomanycases，includingplants，which，frombeingcultivatedunderaclimatehotterthantheirnativeone，becomefittedforastillhotterclimate。Wemaythereforesafelyconcludethatplantscantoacertainextentbecomeaccustomedtoaclimateeitherhotterorcolderthantheirown;althoughthelattercaseshavebeenmorefrequentlyobserved。]
Wewillnowconsiderthemeansbywhichacclimatisationmaybeeffected，namely，throughtheappearanceofvarietieshavingadifferentconstitution，andthroughtheeffectsofhabit。Inregardtonewvarieties，thereisnoevidencethatachangeintheconstitutionoftheoffspringnecessarilystandsinanydirectrelationwiththenatureoftheclimateinhabitedbytheparents。Onthecontrary，itiscertainthathardyandtendervarietiesofthesamespeciesappearinthesamecountry。Newvarietiesthusspontaneouslyarisingbecomefittedtoslightlydifferentclimatesintwodifferentways;
firstly，theymayhavethepower，eitherasseedlingsorwhenfull—grown，ofresistingintensecold，aswiththeMoscowpear，orofresistingintenseheat，aswithsomekindsofPelargonium，ortheflowersmaywithstandseverefrost，aswiththeForellepear。Secondly，plantsmaybecomeadaptedtoclimateswidelydifferentfromtheirown，fromfloweringandfruitingeitherearlierorlaterintheseason。Inboththesecasesthepowerofacclimatisationbymanconsistssimplyintheselectionandpreservationofnewvarieties。Butwithoutanydirectintentiononhispartofsecuringahardiervariety，acclimatisationmaybeunconsciouslyeffectedbymerelyraisingtenderplantsfromseed，andbyoccasionallyattemptingtheircultivationfurtherandfurthernorthwards，asinthecaseofmaize，theorangeandthepe...完整阅读请扫描二维码下载丁香书院APP免费看：