96 THE EVOLUTION OF PLANTS 



supposed that the peculiar characters of Mono- 

 cotyledons (their general loss of secondary growth, 

 for example) may have been due either to their 

 adopting a largely underground mode of life 

 (bulbs and conns), or to then- having taken to the 

 water at an early stage of their evolution. All 

 this, however, is pure speculation; we really know 

 nothing at all at present of the evolution of 

 Monocotyledons; the clearly attested presence 

 of so typical a family as the Palms well back in 

 Cretaceous rocks is as yet quite unexplained. 

 This is one among many indications that the 

 ancestry of the Angiosperms as a whole must go 

 back a good deal further than we have yet traced 

 it, and that the Cycadophyta from which they 

 appear to have been derived, must have belonged 

 to the earlier Mesozoic Floras. 



As we saw in the last chapter, the rise and 

 progress of the Angiosperms was probably due, 

 above everything else, to their adaptation to 

 the contemporary insect life. It is an interest- 

 ing question whether the relation between flowers 

 and bisects had already been established among 

 the Mesozoic Cycads. The flowers of Bennet- 

 tites must have been striking objects when fully 

 expanded, rivalling, in size and modelling, the 

 largest flowers of the present day. We can know 

 nothing of their colours, but the bright tints 

 which we often find in the fructifications of 



