Corynephorus canescens presents two distributional problems in Great Britain; first, as a species with restricted distribution, and second, as one at the northern edge of its distribution. The first problem may be related to the past history of any one dune system and in particular the continuance in time and space of open sandy habitats of intermediate stability; the possible factors limiting Corynephorus at the northern edge of its distribution are considered in the body of the paper. The maintenance of Corynephorus populations is dependent on successful production and dispersal of seed, germination and seedling establishment. Reproductive capacity and seed viability are high. No dormancy mechanisms have been detected. Seed after-ripening is little affected by low temperature (0'C) and the seed is fully ripe eight weeks after anthesis. Germination is slowed down at temperatures below 15'C. Germination in the field is controlled by the availability of moisture for imbibition and its rate by temperature. The later the emergence date of seedlings in the field, the lower the chances of seedling survival. Seedling mortality occurs at a number of stages. It is concluded that the climate beyond the most northerly locality of Corynephorus in Great Britain (57O45' N) is severe enough to have a cumulative effect on flowering date and seed germination sufficient to postpone emergence date of the seedlings beyond the critical time for their survival. Pe3IoMe Bonpoc o pacnpocTpaHeHHH Corynephorus c nescens B BeJIH4o6pHTaHHH pacc;aTPHBaeTCJR B ABYX acneKTax: Bo-fepBbIX, 3T0 BHa c orpaHHxIeHHbIM apeaJioM, BO-BTOpb6X, BejiHKco6pHTafHH1 ipeACTaBjiAeT ceBepy1io o6nacTE apeajia J aHHoro BHXqa. JlepBar npo6iieMa cBs3aHa c H3y'IeHHeM BO3HHKHOBCHHSI H pa3BHTHR A1OHHOrO jiaHAina4)Ta, B xiaCTHOCTH C BOnPOCOM o XJIHTejibHOCTH cyLLIeCTBOBaHHA BO BPeMeHH H npocTpaHcTBe OTKpbIThIX nec:IaHbIX MecTOO6HTaHHtA H HX cTa6HUnbHOCTH. B CTaTi6e o6cyxcaaIoTcJq 4)aKTopbI, onpegenimoLUe pacupeAeneHsHe Corynephorus B ceBepHoll 4acTH ero apeana. COCToaqHHe nonyJIslIHti1 Corynephorus 3aBHCHT OT riPOaYKiHIKH H pacnpocTpaHeHHH ceMAIH, a TalKxe OT YCJIOBHfi[1 popaCTaHHR3 ceM5H. PeupoxyiTHBHas cnoco6HocTb H XKHWHecnoco6HOCTb ceMS1H aOBOJ16bHO Bb6COKH. JlepHoEbI noKOSI y AaHHoro BHIAa He YCTaHOBJIeHbI. CeMeHa nocie Co3pesBHHI 110I'TH He tIYBCTBHTeJThHbl K AeticTBHIO HH43KOtI TeMnepaTypbl, OHH nonHOCTMIO c03peBaio) 'epe3 8 HeAenj1i nocxie JiBeTeHH,I. BcxoxeTT, ceM51H 3aMexursieTCR UPH TemnepaType HH)xKe 150C. BcxoxceCT CMesH B flOj1eb61X YCJIOBHIAX 3aBHCHT OT KoJIHIYeCTBa AocTynHoi BjiarH, a CKOPOCTb npopaCTaHHui 3aBHCHT OT TeMnepaTypb6. xeM fo303AHee CPOKH IO5IBJeHHSI ripopOCTKOB, TeM meHee 6naronpHsTHB, ycnoBsHi AXIR HX pa3BHTHR. OnpeaeneHa rH6eJIb npOPOCTKOB Ha pas3HbIX (aaax pa3BHTHSI. YcTaHOBjieHO, MTO KJIHMaTHIqeCK4e YCJIOBHS ceBepHee rpaHHnbi apeana Corynephorus B BenIHKo6pH4TaHH1H /57 O/45' c.i., OKO[O JIoccHMyTaf CIHIIIKOM CyPOBbI, H CPOKH UBeTeHHA paCTeHHH H nOqBneHHSI nPOPOCTKOB BbIXOAST 3a npeAejibi KPHTH'IeCKHX nepHO)AoB. Manuscript accepted February 1968.