﻿278 BOTANICAL GAZETTE [ai'RIL 



are produced as the result of the heterotypic and homotypic 

 mitoses, occurring in gyninosperms as well as in the majority of 

 angiosperms, is regarded as the more primitive, while that typi- 

 fied by Lilium is interpreted as a derived condition. 



Indiana University, 



Bloomington, Ind. 



*3ij* In justice to the author it should be stated that the publication of the fore- 

 going paper has been prevented for six months by unreasonable delay in the litho- 

 graphing of the plates.— Eds, 



LITERATURE CITED. 



F 



Frye, T. C, '01 : Development of the pollen in some Asclepiadaceae, 



BoT. Gaz. 32:325. igoi. 



GuiGNARD, L., *gg : Le ddveloppement du pollen et la reduction chro- 



niatique dans le Naias major. Archiv. Anat. Microscop. 2 : — . 1899. 



Gregoire, v., '99: Les cineses polliniques chez les Liliac^es. La Cellule 



16:235. 1899. 

 HEUSER/84: Beobachtung liber Zellkerntheilung. Bot. Centralbl, 17 : — , 1884. 

 JuEL, H. O., IQOO: Beitrage zur Kenntniss der Tetradentheilung. Jahrb. 



Wiss. Bot. 35: 625. igoo. 

 MoTTiER, D. M., '97 : Beitrage zur Kenntniss der Kerntheilung in den 



W 



Bot. 30: 169. 1897. 



— 'g8 : Ueber das Verhalten der Kerne bei der Entwicklung des 

 Embryosacks und die Vorgange bei der Befruchtung. Jahrb. Wiss. Bot, 

 31: i8q8. 



W 



. i8g 



5- 



'00: Ueber Reduktionstheilung, Spindelbildung, Centrosomen und 



Cilienbildner im Pflanzenreich. Jena. igoo. 

 '01: Einige Bemerkungen'zu der Pollenbildung bei Asclepias. Ber. 



Deutsch. Bot. Gesell. 29 : 450. 1901. 

 Schnxewind-Thies, J., *oi : Die Reduktion der Chromosomenzahl und die 



ihr folgenden Kerntheilungen in den Embryosackmutterzellen der 



Angiospermen. Jena. igoi. 



EXPLANATION OF PLATES XI-XIV. 

 All figures were drawn from sections with the aid of the Abbe camera 

 lucida and with Zeiss apochromatic homogeneous immersion 2 mm., apert 

 1.40, with compensating oculars 6 and 8, or with Leitz homogeneous immer- 

 sion rV^"^ oculars i and 3. 



Figs. 1-18. Pollen mother-cell of Lilium Martag07i. Figs, i-ii refer to 

 the first mitosis; 12-18 to the second. 



