214 Ferguson . — Development of the Pollen-htbe and the 
* 
the figures above referred to. The nucleolus, if it be present 
at this time, is usually obscured by the dense network. 
Arnoldi (’00) describes the sperm-nuclei in Cephalotaxus as 
being gradually filled with metaplasm. I see no evidence of 
such a process in the development of these nuclei in Pinus . 
When the pollen-tube reaches the egg, its apex is abun- 
dantly supplied with cytoplasm, in the upper part of which 
the vegetative nucleus lies. The sperm-nuclei are just above, 
with the stalk-cell still in contact with the lower portion 
of their cytoplasm. Still higher up, the tube may contain 
many starch grains (Fig. 50). There is never any doubt at 
this time as to the identity of the stalk-cell and the vegetative 
nucleus in the material which I have studied ; but Dixon 
states that they cannot be distinguished, and Coulter (’97) 
describes them as having lost their original outline. 
Archoplasmic areas similar to those figured by Chamberlain 
(’99) have been observed in connexion with the sperm-nuclei, 
but as such granular accumulations may occur at any point in 
the cytoplasm no importance is attached to them. 
Chamberlain (’97) describes a multiplication of the normal 
number of cells in the pollen-grain of Lilium\ and Arnoldi 
(’00), finding more than the usual number of nuclei in the 
pollen-tube of Cephalotaxus , considers that more than one 
vegetative or wall nucleus has been formed. I have twice 
observed such an excess of nuclei in Pinus. Three nuclei 
have been found in the pollen-grain after the vegetative 
nucleus has passed into the pollen-tube (Fig. 51), and two 
nuclei have been seen just passing into the pollen-tube while 
the stalk-nucleus could still be detected in the pollen-grain, 
though it was almost obscured by the dead nucellar tissue 
and is not shown in the sketch (Fig. 45). It is not possible 
to determine definitely from either of these preparations to 
what portion of the male gametophyte the extra cells belong. 
Two wall-cells may have been formed or there may be 
present two stalk-cells ; I am inclined to believe that the former 
is true in Fig. 45 and the latter in Fig. 51, but in neither 
case can one affirm positively, and there is a possibility 
