A CASE OF ASYNDESIS IN PICEA ABIES

OME investigations have treated in detail the embryology and S fertilization of the Gymnosperms (cf.SCHNARF, 1933).Several have d s o dealt with the somatic chromosome numbers of these plants (cf.TISCHLEH, 1926/1027, 1931, 1935/1936 and 1938, as well as .4. and I).LOVE, 1942), but few have been published respecting their chromosome behaviour at meiosis.The chromosome numbers of the Gymnosperms, in contr;i\t to thr condition in the Angiosperms, are remarkably constant even between families and differentiated genera.Polyploidy seeins to occur vcry sparingly.Most of tlie Gymnosperm.s liave twelve chromosome pairs, or 2 n = 2 4 .K. and H. .J. SAX (1933) were able to determine the chromosome nuniber in thc endosperm, which in the Gymnosperms is haploid, for 53 species distributed over 16 genera among the Conifers.The now existing genera of coniferous trees number not fully 50.The investigators just cited found the basic number n = 12 in the majority of the Conifers.Species with deviating chromosome numbers are Cryptomeria japonicti, Tcirotlium distichum, Taiuciniti cryptomerioides, Thuja occidentnlis, T .orientalis, T .plicnta, T .Stcinclishii, Juniperus communis.J .virginiana, J .rigida, and Chamaecyparis Lawsoniana with the basic number n = 11 or 2n = 22, and Pseitdotsugn tnxifolia and the Agathis species (FLOHY, 1936) with the basic number n = 13.For Podocarpus FLORY (1936) gives the following haploid numbers: P .falcatus, -k 12, P .mncrophgllus, -4-19(-20), P. neriifolius, about + 19, P .andinus, about -k 20, and for P .chinensis, $-20.According to TAHARA (1937), the haploid chromosome number of Sciadopitits verticillata is n = 10.Pseudolarix and Juniperus chinensis Pfitzeriana are tetraploid (K. and H. J. SAX, 1. c.) with 211 = 4 4 .Sequoia sempervirens also seems to be polyploid, although no exact chromosome number has been determined.DARK (1932) found about 50 chromosomes in the root-tips of S. sempervirens and considers the species to be tetraploid, while K. and H. J .SAX (1.c.) approximately estimated the total chromosome number for the Hercditns Y X S I I I .20 ENAR