468 



BREAKDOWN OF GENETIC SYSTEMS 



lists, giving the somatic chromosome numbers, show that this is 

 still true of parthenogenetic as well as of aposporous species : — 



Table 69 

 Chromosomes Numbers of Apomictic Species 



Diploid Species 



Chondrilla juncea, etc. (15) 

 Zephyranthes texana (24) . 

 Allium odorum (16) 

 Potentilla argentea forma (14) 



Rosenberg, 191 2. 

 Pace, 1913. 

 Haberlandt, 1923. 

 Miintzing, 1928, 



Triploid Species 



Hieracium horeale forms (27) 

 H. pseudoillyricum (27) . 

 H. Icsvigatum (27) . 

 Chondrilla juncea, etc. (15) 

 Erigeron annuus (27) 

 Eupatorium glandulosum (51) 

 Artemisia nitida (37) 



Taraxacum officinale, etc. (24) 

 Nothoscordon fragrans (24) 

 Ixeris dentata (21) . 



Rosenberg, 191 7, 1927. 



Poddubnaja-Arnoldi, 1933. 



Holmgren, 191 9. 



Chiarugi, 1926 (c/. Weinedel- 



Liebau, 1928). 

 Gustafsson, 1932, 1934. 

 Messeri, 1931. 

 Okabe, 1932. 



Thalictrum purpurascens (48) 

 Elatostema sessile (32) 

 Hieracium boreale forms (36) 

 H. Pilosella (36) 

 Taraxacum croceum, etc. (32) 

 Poa serotina (28) [and 21] 



Tetraploid Species 



Overton, 1909. 

 Strasburger, 19 10. 



Rosenberg, 1917, 1927. 



Gustafsson, 1932, 1934. 

 Kiellander, 1935. 



Rosa canina, etc. (35) 

 Potentilla argentea forma (35) 

 P. TaherncBmontana (35) . 

 Ochna serrulata (35) 

 Taraxacum spp. (45) 



Pentaploid Species 



Tackholm, 1922. 



' I Miintzing, 1928. 



Chiarugi and Francini, 1930. 

 Osawa, 1913 ; Gustafsson, 1932, 



Hexaploid Species 



Potentilla collina {ca. 42) . 



Allium roseum var. hulbilliferum (48) 



Antennaria spp. (84) 



Taraxacum Nordstedtii (48) 



Miintzing, 1928. 

 Messeri, 1931- 

 Stebbins, 1932 b 



1935 «• 

 Gustafsson, 1934. 



Bergman, 



Unstable and Unbalanced Polyploid Species 



Poa alpina {x = 7, 2n = 22 — 38) . 

 Poa pratensis [x = 7, 2n = 49 — 85) 



Miintzing, 1932. 

 Miintzing, 1932, 



