The Origin of Wheat. 137 



modern descendants. It thus differed from the 

 primitive ancestor of dicotyledonous flowers like the 

 daisy and the goose grass, which as we have seen 

 had its parts arranged in whorls of five, not in whorls 

 of three, like the ancestral lily. No single survivor, 

 however, now represents for us this earliest ideal 

 stage ; we can only infer its existence from the 

 diverse forms assumed by its various divergent 

 modifications at the present day, all of which show- 

 many signs of being ultimately derived from some 

 such primordial and simple ancestor. The first step 

 in advance consisted in the acquisition of petals, which 

 are now possessed in a more or less rudimentary 

 shape by all the tribe of trinary flowers, or at least if 

 quite absent are shown to have been once present by 

 intermediate links or by abortive rudiments. There 

 are even now flowers of this class which do not at 

 present possess any observable petals at all ; but 

 these can be shown (as we shall see hereafter) not to 

 be unaltered descendants of the prime type, but on 

 the contrary to be very degraded and profoundly 

 modified forms, derived from later petal-bearing 

 ancestors, and still connected with their petal-bearing 

 allies by all stages of intervening degeneracy. The 

 original petalless lily has long since died out before 

 the fierce competition of its own more advanced 

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