226 A FREE-LIVING SPOROPHYTE 
the Pteridophytes it is illustrated only within a strictly localised area of 
affinity. The course of transition from the dependent ‘embryo to the 
rooted plant, as it is carried out in the individual life, may be held to 
be the most reasonable guide to the same transition in the past. It is 
seen to be occasionally through the intermediary of a protocorm, but 
oftener without. It may ‘be that this indicates correctly the actual course 
which events took; and suggests’ that all vascular sporophytes did not 
achieve their independence in the same way. 
It is of course possible to take an entirely different view of the, 
relations of the two generations from that here presented, and to consider 
the dependence of the sporophyte as being itself secondary, and the 
haploid and diploid phases as having been originally as independent as 
they are seen to be in Diyctyofa. In that case the problem would be 
the converse: viz., to trace the origin of the dependent state of the 
sporophyte. There is, however, no serious basis of fact or comparison 
hitherto adduced, which can place this suggestion upon a footing of 
reasonable probability: it will suffice here to have mentioned that the 
suggestion has been made. 2 
