188 BOTANICAL GAZETTE [MARCH 
represented in jigs. 58-61. The daughter loops are completely sepa- 
rated very early in their migration towards the poles (jig. 62). 
They are also of various shapes. Frequently straight chromosomes 
are present in the daughter star and very commonly the J shape pre- 
dominates (figs. 63,64). Uand V shapes are also present. After the 
chromosomes have passed into the daughter skein stage they show an 
irregular outline with a row of irregular chromatin granules (jigs. 
65, 66). The chromosomes develop into irregular networks, show- 
ing the remains of the original loops, and thus pass into the spore 
tetrad stage (jig. 67). 
During the early germination stages of the microspores the figures 
are again remarkable for the large nucleoli in the cytoplasm (jigs. 
68-70). From the appearance of the nuclei during the several 
divisions, it is evident that the nucleoli do not contribute directly to 
the formation of the chromosomes, but that they are uniformly thrown _ 
out into the cytoplasm, in a fragmented condition, during the earlier 
stages of karyokinesis. 
No study of the achromatic structures was attempted, and though 
some interesting points were observed from time to time, there was 
nothing which calls for special mention. 
SUMMARY. 
1. The first division of the microsporocyte is a true reduction divi- 
sion. 
2. A continuous spirem is formed with a single row of chromatin 
granules. 
3. The spirem passes through and comes out of synapsis without 
a conjugation or division of chromatin granules. 
4. The chromatin granules divide but the linin thread does not 
show a distinct separation. 
5- The continuous spirem shortens and thickens and twists up 
into twelve loops, which are the incepts of the twelve separate chro- 
mosomes. 
6. The chromosomes are arranged in the mother star with the 
loop or head end turned outwards and the spindle threads are attached 
near the ends of the free limbs or about half way between the free 
ends and the head. 
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