FIVE 
THE ADVENT OF FLOWERING PLANTS 
D URING the Permian period, a noticeable change 
in the plant life had taken place. The vegetation, 
which before this time had been composed predominantly 
of seed ferns (pteridosperms), club-moss trees, and a few 
gymnosperms, became more and more gymnospermic, 
until by the end of the period it was overwhelmingly so. 
The conifers appeared, the cycads flourished, and the 
predominance of the gymnosperm types of plants began. 
They came to their highest development in the Triassic 
period which follows the Permian, and they held first 
rank through most of the Mesozoic age. 
The famous petrified forest near Andamana, Arizona, 
is a typical Triassic landscape. In it, the most conspicuous 
trees were the araucarias and other gymnosperms which 
dominate, together with the cycads, nearly all the Meso¬ 
zoic landscapes. The cycads became most prominent. 
They varied a great deal in appearance. Some looked 
like our modern cycads, with their short stems and fern- 
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