82 



MORPHOLOGY OP ANGIOSPERJ1S 



The Number of Chromosomes — Continued 



Plant. 



CHROMOSOME NUMBERS. 



Gameto- 



phyte. 



Sporophyte. 



Year. 



Orchis m ascula 



Himaiiloglossum hircinum. 



Gymnadenia conopsea 



Listera ovata 



Neottia nidus-avis 



Nymphaea alba 



Ceratophyllum submersunt . 



Aconilum Napellus 



Helleborus foelidus 



Paeonia spectabilis 



Podophyllum pelt&lwm. . . . 



Alchemilla alpina * 



Asclepias Cornuli 



" tuberosa 



Asperula 



Crucianetta 



Antennaria alpi/ta* 



dioica 



Silphiurn integrifolium . . . 



" laciniatum 



16 

 16 

 16 

 16 

 16 

 32 

 48 

 12 

 12 

 12 

 12 

 12 



8 

 32 

 in 

 in 

 12 

 10 

 40-50 

 12-14 



8 



8 



(32) 

 (32) 

 (32) 

 (32, 

 (32) 

 (64) 

 (96) 



24 

 (24) 



24 



mostly 16 



(24) 



16 



32 



20 



20 



24 



20 



40-50 



counted 20 



(16) 



16 f 



Strasburger '"' 



Guignard 26 



Guignard D ' J 

 Strasburger 72 

 Strasburger 101 

 Oyerton 28 

 Strasburger 20 

 Strasburger 3 " 

 Overton 28 

 Mottier 34 

 Murbeek 9 * 

 Strasburger 9G 

 Frve " 

 Lloyd 105 



Juel 88 



Merrell ' 

 Land 8l 



1888 

 1888 

 1888 

 1891 

 1891 

 1898 

 1900 

 1902 

 1893 

 1888 

 1894 

 1893 

 1895 

 1901 

 1901 

 1901 

 1902 

 19(12 

 1900 

 1900 

 1900 

 1900 



It is evident from the table that Strasburger and Guignard 

 were pioneers in this work and that they still remain the most 

 active contributors. It is of interest to note that when atten- 

 tion was first directed to this subject, the number of chromo- 

 somes reported for the sporophyte, while exceeding that of the 

 gametophyte, was not precisely twice that number. The sub- 

 ject is one of great difficulty, and doubtless the countings of 

 competent investigators have often been influenced by their 

 theories, while their followers have been content too often with 

 confirming a reported number. Variations from the character- 

 istic number are numerous. In the gametophyte the number 

 of chromosomes in the antipodals is frequently irregular, with 

 a tendency to higher numbers ; but an explanation may be found 

 in the irregular nuclear divisions which present some of the 

 characters of amitosis (Miss Sargant 41 ). Variations are even 

 more frequent in the sporophyte, but it is well known that 

 mitoses are frequently irregular, and it is easy to imagine that 

 a chromosome may fail to split or that an unequal distribu- 



* Parthenogenetic. 



f More than 16, probably 24, in endosperm. 



