346 Note on the Gametophytes of Dacrydium. 
and the pressure of the pollen-tube. 1 It does not occur in archegonia 
which have not been reached by a pollen-tube. 
The archegonia of D. Coleusoi are each surrounded by a layer 
of jacket cells. The shape of the mature archegonium is worthy 
of notice owing to its extreme length, for it extends to the middle 
region of the prothallus. It is shaped roughly like an elongated 
cone, the widest part being that in connection with the pollen-tube; 
the lower end is very narrow. In the event of a pollen-tube not 
reaching the archegonium, the upper end is however rounded and 
narrower. 
The cells of the prothallus have by this time become hi- or tri- 
(and in some cases quadri-) nucleate : a multinucleate condition 
is also recorded in Podocarpus and Phyllocladus. 
V. General Remarks. 
These observations on the gametophytes of Dacrydium, 
fragmentary as they are, yet suffice to indicate two interesting 
facts. The first is the general resemblance of the male 
gametophyte of Dacrydium to this structure in Podocarpus 
and Phyllocladus, the second is the much closer resemblance of the 
female gametophytes of Dacrydium and Phyllocladus to one 
another, than to that of Podocarpus. This is all the more re¬ 
markable as on general grounds the genus Dacrydium has generally 
been regarded as much more closely allied to Podocarpus than to 
Phyllocladus ; indeed the latter genus has by many writers been 
placed in a separate order or sub-order, along with Taxus, 
Cephalotaxus and Torreya. Mr. Brooks and the writer have pre¬ 
viously pointed out that the resemblance of Phyllocladus to the 
Taxeie is not at all striking, while Miss Young has brought forward 
important evidence in favour of including Phyllocladus with the 
Podocarpeae. The structure of the gametophytes of Dacrydium 
Coleusoi affords a striking piece of evidence in support of this 
opinion. 
The University, 
Leeds. 
October 20th, 1911. 
1 Young (1910), p. 86. 
WALTER STILES. 
