﻿Hance: Pollen development in Zebrina pendula 69 



Atkinson, G. F. Studies on reduction in plants. Bot. Gaz. 28: 



1-26. pi. 1-6. 1899. 

 Farmer, J. B., and Shove, D. On the structure and development of 



the somatic and heterotype chromosomes of Tradescantia virginica. 



Quart. Jour. Mic. Sci. 48: 559-569- pl- 42, 43- I905- 

 Gates, R. R. Pollen development in hybrids of Oenothera lata X 



0. Lamarckiana, and its relation to mutation. Bot. Gaz. 43: 



81-115. pl. 2-4. 1907. 

 Gates, R. R. The behavior of the chromosomes in Oenothera lata 



XO. gigas. Bot. Gaz. 48: I79-I99- pl- 12-14- 1909. 

 Guyer, M. F. Spermatogenesis of normal and hybrid pigeons. 



Univ. of Cincinnati Bulletin No. 22. 2 pl. 

 Miyake, K. Ueber Reduktionsteilung in den Pollenmutterzellen 



einiger Monokotylen. Jahrb. Wiss. Bot. 42 : 83-120. pl. 3-5. 1906. 

 Mottier, D. A. The behavior of the chromosomes in the spore 



mother-cells of higher plants and the homology of the pollen and 



embryo-sac mother-cells. Bot. Gaz. 35: 250-282. ;p/. 17-14. I903- 

 Mottier, D. A. The development of the heterotype chromosomes 



in pollen mother-cells. Ann. Bot. 21: 309-347. pl. 27, 28. 1907. 

 Overton, J. B. On the organization of the nuclei in the pollen 



mother-cells of certain plants, with special reference to the per- 

 manence of the chromosomes. Ann. Bot. 23 : 19-61. pl. 1-3. 1909. 



E^xplanation of plates 3-5 

 The drawings were made at table level with the aid of a Leitz camera lucida and 

 ing a Zeiss 2 mm. apochromatic objective and a No. 12 ocular. Fig. 27 is the one 



•>hase of Heterotypic Division 

 5 moved to one edge of the n 



Smaller nucleolus has beer 

 Nucleus has spread to fil 

 beginning to form. Only c 

 Beginning of synapsis. 



to form the individual pairs of c 



