Nov., 1914.] Stamens of Smilax herbacea. 361 



Sauer, when investigating Convallaria majalis (10), found that 

 there was a resting period after the last archesporial division, 

 but that in a short time a chromatin network was fonned. The 

 nucleous described as being visible from the beginning, fragments 

 in the later stages forming several micronucleoli. He sa^^s that 

 there is a clear area in the nucleus and that the continuity of the 

 spirem is very evident. After synizesis a loosening and unwinding 

 of the thread begins. The linin thread becomes thicker and the 

 chromatin granules elongate. Altho the spirem is shorter it 

 occupies the whole cavity and the division of the granules is 

 apparent. After this stage the doubleness of the spirem is no 

 longer visible. The spirem is next thrown into sixteen loops 

 which later divide into sixteen chromosomes. The first division 

 of the chromosomes in the microsporocytes is transverse and 

 therefore qualitative. 



Miss Hyde found in Hyacinthus orientalis (3), a definite 

 network in the microsporocyte, but fails to discover any accumula- 

 tion of chromatin material that might be interpreted as proto- 

 chromosomes. She determined, however, that the complicated 

 spirem was continuous, undergoing synizesis, looping, and finally 

 breaking into eight well individualized chromosomes. 



Miss McAvo3% in her observations of the reduction division 

 in Fucshia (7), found protochromosomes which seemed to stretch 

 out and form a continuous spirem with chromatin granules. 

 The spirem undergoes synizesis after which the delicate thread 

 soon begins to thicken and in a short time shows loops which 

 lie along the periphery of the nucleus. These loops, fourteen in 

 number, break apart to form fourteen chromosomes. 



The study that she made of Oenothera biennis (8), served 

 to confirm the results stated in her previous paper in as much 

 as she found a retici.ilum and protochromosomes which in turn 

 formed a continuous spirem that could be traced its entire length. 

 The synizetic knot is not so tight as in some plants and even 

 in this stage she was able to trace out much of the spirem. Loops 

 were formed which break apart forming seven chromosomes. 



MATERIALS AND METHODS. 



The primary purpose of this study was to observe the reduc- 

 tion division in the microsporocytes of Smilax herbacea and 

 also to incidentally consider any peculiarities in relation to the 

 degeneration of normal stamens to vestigal structures or to 

 their complete disappearance. It was found, however, that the 

 material available did not give the more critical stages bearing 

 upon the second part of the problem. 



The material used in the investigation was collected from the 

 first week in May, 1913, at Columbus, Ohio, to the middle of 

 June, 1913, near the Lake Laboratory at Cedar Point. The 



