4 BOTANICAL GAZETTE [july 



chromosomes in such uncut nuclei can then be counted with absolute 

 accuracy, either in the prophase of the heterotypic mitosis before the 

 disappearance of the nuclear membrane, or in the telophase after the 

 walls of the daughter nuclei are formed. In nearly every individual 

 examined, large numbers of such cases, all yielding the same result, 

 were counted before the number was finally determined upon. The 

 chromosomes could also be counted in certain positions on the 

 spindle, particularly in anaphases, but in metaphase they were usually 

 too closely grouped to allow of satisfactory counting. 



In the second division, particularly in the forms having seven 

 chromosomes as the gametophytic number, the chromosomes could 

 be counted with certainty in almost any stage of mitosis. The thinner 

 sections were used chiefly in the study of spirem and synapsis stages, 

 although here also the comparatively short length of the thickened 

 spirem frequently made it advantageous to study uncut nuclei in 

 which the spirem could be followed throughout its length. 



Of the various stains Heidenhain's iron-hematoxylin was found 

 to be superior for chromosome counting and for clear differentiation 

 of chromatic structures in nearly all stages of synapsis and reduction, 

 safranin-gentian being used occasionally for comparison or for 

 differentiating particular cytoplasmic structures. Orange G was 

 also used with the iron-alum stain for bringing out clearly certain 

 special features, particularly the protoplasmic connections between 

 mother cells, which will be described later. 



Description 



EARLY STAGES 



Some of the very early stages of the anthers, previous to the forma- 

 tion of mother cells, have been studied particularly with the purpose 

 of tracing the origin of the bodies which were called heterochromo- 

 somes in my first paper. The provisional use of the name was 

 based on the very close resemblance of these bodies to the chromo- 

 somes in appearance, and their frequent presence close by, or in some 

 cases apparently attached to, the heterotypic spindle. They were 

 not stated to pass undivided into one of the daughter nuclei, as 

 misquoted by Tischler (32), but to remain outside in the cytoplasm 

 where they gradually disappear. The study of their early history 



