154 Johnson . — On Arceuthobium Oxycedri. 
This latter process does not keep pace with the former ; the 
basal part of the ovarian papilla is pressed out of shape by 
the developing seed, which is also causing considerable pressure 
on the pericarp, so much so that the inner part of the meso- 
carp is completely crushed, an obliteration which does not 
extend to the outer part of the mesocarp, the walls here 
having begun to be thickened and lignified. The seed comes 
to have a relation to the pericarp similar to that of the proto- 
plasm to a cell-wall in a turgid cell. The mutually exerted 
pressure is further and greatly increased by the formation of 
the thick layer of viscid cells, a formation which has proceeded 
with the other changes in the production of the fruit. At 
maturity the degree of tension is so great, the weakest part 
of the pericarp gives way. This spot has already been 
prepared by the development of the meristematic zone at the 
base of the fruit. This zone is torn in two horizontally, the 
elasticity of the stretched pericarp comes into play, the ‘seed’ 
(its shape helping) is forcibly ejected enveloped by the 
endocarp. The viscid cells are torn across at their peripheral 
ends, which are left on the inner surface of the mesocarp. 
The cell-sap of these cells escapes and gives to the viscid 
walls a more sticky consistency, by which the seed is enabled 
to adhere to the host-branch on which it may fall. It has 
been noticed that the viscid layer is not present at the anti- 
radicular end of the seed. 
5. The Male Flower of A. Oxycedri. 
Sir W. J. Hooker 1 first figured the male flower magnified 
ten or twelve times. Examination after greater magnification 
of a flower just before expansion shows that the stamen con- 
sists of a sessile anther, bilocular at first, becoming unilocular 
by the breaking down of the separating trabecula in the usual 
way. The wall of the anther consists of one layer of cells 
only, and it is curious that this, though it is the epidermis, 
1 W. J. Hooker, op. cit. on p. 142, Tab. xcix. 
