22 BOTANICAL GAZETTE fe 
form of the chromosomes and the mode of separation at the 
nuclear plate would not permit of classification into the types 
suggested by Beliaieff.* It is quite reasonable to believe that in 
mitosis, where the size and proportional dimensions of the chro- 
mosomes vary, as they are so well known to do, a great variety 
in the form of the chromosomes may exist, and that, correspond- 
ingly, there may be great variation in different species mani- 
fested in chromatin figures and evolutions, even where the same 
result is finally obtained. 
In the peculiarities of the second mitosis of the pollen 
mother cellin Z7illium grandiflorum, there is presented a distinct 
type in the evolutions of the chromosomes during the reducing 
division. Considerable interest attaches also to the peculiarity 
of the large chromosomes during the anaphase and metaphase 
of the first mitosis, where there is an appearance of eight denser 
portions of chromatin in the chromosomes, arranged in four 
pairs in such a way as to suggest two tetrad groups in a single 
segment of the spirem. In connection with this, it is interesting 
to note, that, while in Zriliium gvandifiorum during the first | 
mitosis in the pollen mother cell there are only six chromo- 
somes, in a number of the Liliacee there are.twelve. This 
indicates, possibly, that the segments of the spirem in Trillium ' 
here represent four chromosomes, fused end to end (quadri- 
valent), instead of two (bivalent), which is usually the case as 4 
result of the pseudo-reduction. Avisema triphyllum, according tQ_ 
my studies on this species, also presents a distinct type, in that — 
the reducing division, though following the longitudinal] division, © 
occurs during the first mitosis. a 
That there should be variations in the evolutions performed 
by the chromosomes in different plants, such as to represent | 
different types, is what one might expect, not only in view of the — 
great variations in the size and form of the chromosomes 12 — 
different plants, representing different types of chromosomes, but — 
also in view of the tendency to variation so manifest in many of | 
re: *BELIAIEFF, W.—Ueber die Reductionstheilung des Pflanzenkernes (Vorlaufige : : 
Mittheilung). Ber. d. deutsch. bot. Gesells. 16 27-34. 1898 t 
