152 F. IV. Oliver. 
living genus of Gymnosperms known to possess a ruminated 
endosperm. 
The young ovules (which emerge from the bud at the end of 
May for pollination) if examined in April whilst still immature shew 
a free nucellus enclosed in a single integument. Early in May a zone 
is intercalated at the base of the ovule and from this zone the aril 
subsequently arises. By the winter the ovules are fertilised and 
the beginnings of embryonic development initiated. The aril has 
meanwhile grown up to the micropyle. The further extension of 
the seed is intercalary, so that by the following summer an 
extensive zone has been added at the base—indeed the whole seed 
with the exception of its immediate apex originates in this way. 
In a ripening seed of the second year taken at the end of June, the 
portion in which nucellus, integument and aril are free from one 
another, may represent less than ^ the entire length of the seed. 
In the downward extension of the seed, however, all the parts free 
above are anatomically distinguishable—nucellus, integument and 
aril. The transverse section represented in fig. 6 being across the 
middle of a seed taken at the end of June in its second year, the 
various layers are consequently continuous with one another. 
The outer, shaded zone a represents the aril with its numerous 
gum-canals. At v (in black) are the two sets of vascular bundles 
which in this region of the seed belong to the aril. The unshaded 
ring sc corresponds with the outer part of the integument. It is 
the zone in which the stone or sclerotesta will subsequently differ¬ 
entiate. The shaded belt i is continuous with the inner part of the 
integument, so that sc and i together may be regarded as the equiva¬ 
lents in the body of the seed of what is a free integument above. 
Within the integumental region is a colourless border n, this is the 
downward continuation of the nucellus. The containing line mw 
marks the edge of the prothallium, the central area ps being occu¬ 
pied by the (at this time) translucent, watery endosperm. Well 
marked foldings between the inner portion of the integument (i) 
and the nucellus (») are already present. Actually a number of 
longitudinal ridges, due to the active, localised, inward growth of the 
integument in a radial direction, are present though they have not 
yet attained their full dimensions. These ridges are the rumination 
plates which form so conspicuous a feature in the ripe seed and by 
the agency of which the endosperm is divided and sub-divided into 
bays. The intrusive ridges run mainly in a longitudinal direction 
though they occasionally anastomose. The internal edges of these 
ridges are not straight but sinuous, so that in radial section a ridge 
