H 2 
Walter Stiles. 
products it seems clear from the enlarged condition of the phloem 
and cortical tissues on the lower sides of the islands that only a 
small quantity, if any, of the products elaborated by the branches 
could have been conveyed away to feed the roots. It is possible, 
however, that a certain amount of sugars may have been carried 
by a descending current through the xylem of the trunk, as has 
been shown to be the case in the birches, sugar-maple, etc. 1 
Whether the xylem in the conifers affords a channel for the 
conduction of sugars, etc. in normal cases, does not appear to have 
been determined. 
The peculiar conditions of life of these living islands on the 
ringed wooden poles of the trees, suggests a comparison with a 
partial parasite, such as Viscutn. These islands, like the parasitic 
Misletoe plant, are dependent on the tree trunk for their water 
supply, but otherwise they are independent, since they are able to 
elaborate and use their own metabolised products. That the 
existence of branches under such conditions is possible, or rather 
that the trunk is able to supply them with water, is somewhat 
contrary to expectation, and it would be a matter of interest to 
determine for how long a time the water current would be main¬ 
tained in a completely ringed stem to support life in isolated 
portions of the cortex. 
1 see Pfeffer. “ Physiology of Plants.” Eng- Ed., Vol. I, pp. 
262, 574, 578, where the author discusses the question of 
translocation in the wood. 
A NOTE ON THE GAMETOPHYTES OF DACRYDIUM. 
[With Four Figures in the Text]. 
I. Introduction. 
LTHOUGH we now have a fairly wide knowledge of the early 
stages of development of the male gametophyte of the 
Podocarpete, 1 yet as regards the female gametophyte and the later 
stages of development of the male gametophyte our knowledge at 
present is limited to the observations of Coker 2 on a single species 
of Podocarpus and those of Miss Young 2 on a species of Phyllocladus. 
1 Thibout (1896), Coker (1902), Jeffrey and Chrysler (1907), Young 
(1907), Burlingame (1908), Noren (1908), Thomson (1909 1 ), 
Brooks and Stiles (1910), Young (1910). 
2 Coker, op. cit. 3 Young op. cit. 
