Ali BKJUHU FH.yDl N UOTANISKI-: HAVE I KJOliliNHAV N, No. 1U3. 



Sr/Kijii/ lir llfrrililii\ \', l'l'J'i. 



CHROMOSOME NUMBERS IN THE GENUS 



HYPERICUM 



(A prfliiniiKuy iintc) 



liv mi: I. S mi:lsi:\ 



I.AHOIUrOllY Ol- thi: liOIANICAI. (lAUDMNS Ol TMi; IMMlisri Y. (OI'IIN II A(.I.N 



OM.N' liw ( vl(»l()^,'i(:il invcsli^ations Iimnc Imm-m iikuIc Nvilhin llie 

 ordcr (iiittifcnilts. Tischlkh (1921) slates tlic miinbcr ol cliro- 

 inosoincs ni" Iw'o species only; Thkih (19111 has invfstij,'iil('<l Ctdrcinid 

 l'rruhii and lixes tlie lKii)loi(l mimluT ol' cliroinosoines at aboiit 24; 

 (lOHKN SriAHT (1916) has oxainined Thcd sincnsis aiul lixes the 

 ha|)ini(i luiiniM'i- of chroniosomes at 15. While iiivesti^atinj^ tiie eiii- 

 hiV()lof,'y ni Hiipiriciim j)i'rfor(itum and H. nuiciihitiiin.Scii'SAiw (1914) 

 Motieed thai Ihesc |>lanls seeni to ha\'e a irreal nuiiihcr ol' chromosomes 

 of ^inaJl si/e; ScHNAHK has, howex'er. nol imcslijL^aled this ([iiestion 

 iii detail. 



A evtolof^ical iiixcslif^ation wilhiii (iiillifcidlcs iiiay, Ihcrriorc. l)e 

 f)f sonie interesl. I ha\t' examined ditlerent species belongiiij^ lo llie 

 f^oniis IIiifK-ricimi. Hu- only genus withiii (iiiltifcrdlcs, \vhich I was ahle 

 to iincstigate. 1 ha\(' coHected the inaterial in tlu* Hotanical (iardens 

 of the I iijxcisily. excepi Hi}f)criciini pcrfornliiin. H. nuuuldtiiin. II. 

 dciiliiin, II. hir.siilniu and //. inonldiuim, whicli I liave collected Irom 

 wiid <,'ro\ving piants in North-Seaiand. 'i'he ohject was an investiga- 

 lion ol tin- »hroinosonie niiml)ers: the reduction divisifin was investiga- 

 ted in the pollen inothei -cells. Carnoy's mixture ol alcohol-chloro- 

 form-acetic acid was used as means of fixation, and the result was 

 excellent, l'or the staining I liave exclusively iise«! IIkidknhain's iroii 

 lia'inatoxylin. 



THE RESTING NUCLEUS. 



The resling hik lens in Ihe iK)llen niother-cells has invarial)ly one 

 niirlroliis. which is glohular. Il is difficiill to define the structure of 

 the nuclnis. hnl il ap|)arenlly consists ol a netled, slightly stainal)le 

 groiind suhstance wilh highly stainahle chroino ■enters. The nninher 

 of chroinocenlers is nol constant and does not correspond lo llie iium- 

 her of chroinosoines; thus, for insiance, Ihjpcriniw monlduum has 8 



