33i 
Actinostrobus pyramidalis , Miq. 
the cells near the middle of the prothallus, and especially those near the 
advancingembryo,becomebinucleate or four-nucleate. One such four-nucleate 
cell is drawn in Fig. 22. A dividing nucleus in a prothallus cell is shown 
in Fig. 23. The chromosomes are very thick, and it is not possible to show 
more than about half of them in a drawing. The number passing to each 
pole is eight. A single dividing nucleus in a prothallus cell is quite com- 
monly met with, but only one case has been seen of two dividing nuclei side 
by side in the same cell. This, however, serves to establish the fact that 
the four-nucleate cells are derived from the binucleate by simultaneous 
mitosis of the two nuclei. 
The binucleate and four-nucleate cells are exactly like those of 
Widdringtonia and Callitris , and it is here necessary to correct a com- 
pletely inaccurate statement made by Coulter and Chamberlain ( 5 ) in 
reference to this point. They state (p. 262), ‘ Saxton has observed the 
same free nuclear division in the primary endosperm cells of Widdring- 
tonia ’ (primary cells are defined on the same page as 4 those open towards 
the centre of the sac i. e. the alveoli), ‘ but in this case the cells usually 
become only binucleate (occasionally multinucleate), and this binucleate 
or multinucleate condition persists in the permanent tissue, as if the last 
stage of other forms were omitted in Widdringtonia .’ Without further 
comment, I add the following extracts from my own statements in the two 
papers cited by Coulter and Chamberlain in this connexion : ‘ A large 
number of nuclear divisions have been seen in the “alveoli”, certain features 
of which strongly recall the peculiar divisions described by Lawson as 
occurring at this time in Cryptomeria. The wall between the nuclei, 
however, is always developed, but in cases where its width does not nearly 
equal the diameter of the cell, it is just possible that wall and fibres may 
disappear again, and thus give rise to a binucleate cell. It has not been 
demonstrated, however, that binucleate cells ever originate in this way ’ 
( 20 , p. 35). ‘The cells at first formed are invariably uninucleate . . .’ 
( 19 , p. 167). ‘ It seems perfectly clear . . . that the binucleate (and in some 
cells multinucleate) condition arises by karyokinetic division of the original 
single nucleus ’ ( 19 , p. 170). 
This bi- and multinucleate condition of older prothallial cells is more 
widely distributed in the Pinaceae than the literature of the subject would 
indicate. They are also known to occur in the Taxaceae, having been 
recorded in Podocarpus (Coker ( 3 ) and Gibbs (8)), and Taxus (Jaeger ( 11 )). 
In Cephalotaxus also, the writer has had the privilege of examining some 
excellent preparations made by Mr. L. A. Boodle, in which several free 
nuclear divisions may be seen in a single cell of the prothallus. 
From the writer’s preparations of other Conifers, and published records, 
the following facts have been noted : In Araucaria Cookei binucleate, and 
occasionally four-nucleate, cells seem to be more or less the rule in the 
