303 



(). The roses of the types 1 — 3 showing all Ihe chiomosomes 

 in paired conciilion in the dinkiiiesis have no donl)l exchisively 

 sexnal rej)rocluclion. At any rale Ihere are no reasons for not 

 assuniin<5 Ihal. 



7. Triploid roses (type 4) showing in Ihe heterolype division 7 

 paire(l and 7 single chromosomes may be inlerpreled as hybrids 

 derived from Iwo such sexnal forms possessing respeclively 7 and 

 14 chromosomes in Iheir germ cells, The reduclion division in 

 the pollen mother cell is in quile accordance with the hybrid- 

 scheme of Drosera. To Ihis group belong two bushes of chincnsis 

 (indica) from Kew, (jdllica x cinnamomea (»turhinata» from Kew), 

 aciciilaris x cinnamoined (from Uppsala), blanda x pendnlina (Uppsala), 

 and centifolia major bort. 



8. One, perhaps more, of the bnshes representing the type 8 

 showing 14 bivalent and 7 single chromosomes in the diakinesis 

 can in the same way be explained as a hybrid originated from 

 normal sexnal parents, the one diploid, the other hexaploid. The 

 bush in (jnestion (»U. 31» in Horlus Bergianus, Stockholm) is slated 

 to be a hybrid of pendnlina (and acicularis or'_nntkana). This form, 

 too, realizes Ihe reduclion division in accordance with the Drosera- 

 scheme. In some anlhers the pollen molher cells carry out a Ihird 

 division afler the homotypic. To Ihe same type (8) belong three 

 other invesligated forms, brilzensis, a native of Kurdistan, one 

 variety of damascena, and one specimen ot involnla. These forms 

 are to be discussed in the detailed publication. 



V). All the examined form belonging lo the seclion Caninae in 

 Ihe widesl sense (see point 2), i. e. mosl of the roses distribuled 

 in Europé, North Africa and West Asia, are characlerized by the 

 occurrence of bolli bivalent and single chromosomes in Ihe hetero- 

 lype division. They constitute the types 5 — 7 in Ihe chromosome 

 lable and have Ihen 7 paired and 14 or 21 or 28 single chromo- 

 somes. The forms of villosa (among them pomifera) and rnbrifulia 

 have 7 paired plus 14 single = 28 chromosomes. All the forms 

 belonging to the old complex species canina, dnmetornm, glanca 

 and coriifolia are penlaploid: 7 paired plus 21 single = 3ö chro- 

 mosomes (aboul 30 invesligated forms). The same chromosome 

 combinalion characterizes also certain forms of sti/losa, Ihe exami- 

 ned forms of tonienlosa, and several species of the subseclion 

 Rnbifjinosae, for instance rubiginosa, Seraphini, sijlvicola, micrnntha, 

 nilidnla, sicula, hnngarica, and certain forms oi glutinosa. I suppose 



