312 BOTANICAL GAZETTE [may 



Conclusion 



F 



According to the present interpretation of the value of chromo- 

 somes, in Nepiir odium molle Desv, there is present an antithetic 

 alternation of generations marked by the number of chromosomes. 



Apogamy in Nephrodium presents a new situation, where the 

 sporophyte is developed with the haploid number of chromosomes. 

 This seems to be an abnormal case, but it must be admitted that it 

 shows that the number of chromosomes is not the only factor which 

 determines the characters of the sporophyte and gametophyte. 



The University of Chicago 



Note.— After this paper was in type, Strasburger's *'Chromosomenzahlen, 

 Plasmastrukturen, Vererbungstrager und Reduktionsteilung" (Jahrb. Wiss. Bot 

 45:479-568. ph. j-j. 1908) appeared. It not only presents results of investiga- 

 tions on Lilium Martagon dealing with the chromosome situation during embryo 

 sac formation and pollen tube development, but it also contains voluminous data 

 concerning plasma structure, chromosomes as bearers of hereditary characters, 

 and the phenomena of the reduction division, the discussion being based upon 

 works of various invesitgators of both plant and animal cells. 



LITERATURE CITED 



I. De Bary, a., Ueber apogame Fame und die Erscheinung der Apogamie im 

 . Allgemeinen. Bot. Zeit. 36:449-487, pL 14, 1878. 



2- , Vergleichende Morphologie und Biologie der Pilze (Generations- 



wechsel:i33). 1884. 



J 



Anti 



4 



thetic alternation of generations. Annals of Botany 9:441-447- ^^95- 

 . Blackmax, V. H., On the fertilization, alternation of generations, and 

 general cytologj- of the Uredineae. Annals of Botany 18:323-373- P^^ ''" 



S.2I' 



24. 1904. 



5 



apo 



:5is." 



49~ 



* 'V "^'^e*^*- o • ^^y^A^o. xyu4. 



6. Bower, F. O., On some normal and abnormal developments of the oophy 



in Trichomanes. Annals of Botany 1:269-315. ph. 14-16. 1888. 

 7- -_ , On antithetic as distinct from homologous alternation of genera 



8. 



tions in plants. Annals of Botany 4:347-370. 1890. 



-, Opening address in the British association (Bristol meeting). Nature 



9 



66-69, 1 1 2-1 14. 1898. 



spore 



V. General 



comparisons and conclusions. Phil. Trans. Roy. Soc. B 196: I9i-2S7- ^9°i- 

 Braun, a., Die Frage nach der Gymnospermie der Cycadeen, erlautert 



