60 

 Ancient trees. 



Lepidodendrons like CycopodiTims. 



Galamites like Equisetiums. 



Perus proper. 

 G^muosperras. 



Tlie first two are distinctly xeropliytic in structure, lience the 

 question whether the original trees grew in deserts or tropical 

 wet regions. 



Deciduoud versus evergreen. 

 Drouth and cold, alternating with moisture and heat prodiice deciduous 

 trees. Uniformity of conditions produce the evergreen. Exception 

 to this evergreens which increase towards the north. One reason is 

 advantage of "being reafly for work at all times without beginning 

 again. Power to resist sudden changes as summer frosts. 



Sclerophyll or hard-leaved type, as laurel or holDy. 

 Needle-leaved or northern types. 

 Soft-leaved or southern types. 



The first is fitted to resist iinfavorable conditions, as cold 



and rain together and drouth and heat ; hence this type of plant is 



largely developed in Mediterranean region, in California, along the 

 Gu.lf coast, etc. This leaf a kind of half-way condition. 

 ^y( Light. iregetative Reproduction. Protection. 



Tree, deciduous tree. 



'Pfee, evergreen needle, tropical, hard-leaved. Lianas. Rhizome, 



Bulb, Rosette, Annual. 



