‘ 
292 BOTANICAL GAZETTE [APRIL 
chromatic material. The stages from the loosening of the synaptic 
knot to the formation of the gemini are passed through rather 
rapidly; and the changes apparently take place in all parts of the 
nucleus at practically the same time. There does not seem to be 
any definite “second contraction,” but rather a continuous shorten- 
ing and thickening of the threads from the time the thin loops 
first appear until the gemini are formed. 
The two members of a geminus are generally united at one end, 
but they are often found entirely separate or united throughout 
their length (figs. 11 and 12). Their appearance in figs. 10 and 
tr would indicate that the loops from which they arose consisted 
of both chromatin and linin, and that in the formation of gemini 
at least a part of the linin is discarded. Diakinesis is apparently 
of considerable duration and affords an excellent opportunity for 
counting the chromosomes. The reduced number is evidently 8. 
_ The nucleolus appears at this stage as a pale and somewhat 
irregular body (figs. 10-12). 
The succeeding stages present no sareoned features. The first 
division separates the two members of the gemini, but there is no 
evidence of a longitudinal split in the chromosomes during the 
anaphase (fig. 13). During interkinesis the daughter nuclei of the 
first division approximate somewhat a resting condition. A rather 
definite nuclear membrane is formed, a pale nucleolus appears, the 
chromosomes become more or less vacuolate, and are connected to 
some extent by indefinite linin threads (fig. 18). It is usually 
possible at this stage, however, to make out the separate chromo- 
somes and to determine definitely the reduced number, 8. The 
second division is a typical homotypic division. 
It will be noted that the condition described for the buckwheat 
corresponds closely with the “hétérohoméotypique scheme’”’ of 
GREGOIRE (17, p. 233). His “‘scheme”’ may be briefly outlined as 
follows: In the early prophase (p. 243) of the reduction division, 
the nuclear mass becomes resolved into a number of fine threads, 
each of which is the equivalent of a somatic chromosome. This 
is the leptoténe stage. These threads, the ‘‘gamomites,’’ become 
arranged in pairs (zygoténe stage), which afterward fuse to form a 
series of independent loops, the pachyténe loops. These pachy- 
