270 
At the base of the ovuliferous scale on the upper sur- 
face two ovules are borne, the micropyle of which points 
towards the axis of the strobilus. 
In a very young ovule the micropyle has on both 
lateral sides two rather long slips, always corresponding 
with the place, where the two ribs are to be seen 
later on. 
The integument is composed of the three characteristic 
layers, which are of equal size in the beginning, but soon 
the sclerotesta gets the greater development and is the 
most conspicuous one. In the mature seed the outer soft 
layer is reduced to a thin dry membrane, which has often 
disappeared already, but in Pin. canariensis for example 
it still remains as a definite layer, in other cases as in 
Pin. sylvestris a. o. it is prolonged in the well-known 
thin wing. 
The endotesta too becomes reduced to a thin brown 
layer covering the inner surface of the testa. 
In an early stage nucellus and integument are completely 
free from one another but further growth takes place in 
the chalazal region, so that in the mature condition they 
are only separated in their apical portion. 
On the sclerotesta two ribs are distinct, according to 
their corresponding sutures the scale splits easily when 
pressed. 
The integument originates often as two separate pro- 
trusions (Eichler, 64). 
The vascular supply has disappeared in connection with 
the less developed outer and inner layer of the testa, 
remaining only as a tracheal plate at the base of 
the seed. 
