PAST HISTORIES OF PLANT FAMILIES 129 



the Marattiace/e, has descendants living at the present 

 day, though the family is now represented by a small 

 number of species belonging to but five genera which 

 are confined to the tropics. Perhaps the best known 

 of these is the giant " Elephant Fern ", which sends up 

 from its underground stock huge complex fronds ten or 

 a dozen feet high. Other species are of the more usual 

 size and appearance of ferns, while some have sturdy 

 trunks above-ground supporting a crown of leaves. 

 The members of this family have a very complex 

 anatomy, with several series of steles of large size 

 and irregular shape. Their fructifications are charac- 

 teristic, the sporangia being placed in groups of about 

 five to a dozen, and fused together instead of ripening 

 as separate sacs as in the other fern families. 



Impressions of leaves with this type of sorus (group 

 of fern sporangia) are found in the Mesozoic rocks, 

 and these bridge over the interval between the living 

 members of the family and those which lived in 

 Palaeozoic times. 



In the Coal Measure and Permian periods these 

 plants flourished greatly, and there are remains of very 

 numerous species from that time. The family was much 

 more extensive then than it is now, and the individual 

 members also seem to have reached much greater 

 dimensions, for many of them had the habit of large 

 tree ferns with massive trunks. Up till Triassic times 

 half of the ferns appear to have belonged to this family ; 

 since then, however, they seem to have dwindled 

 gradually down to the few genera now existing. 



On the Continent fossils of this type with well-pre- 

 served structure have long been known to the general 

 public, as their anatomy gave the stones a very beautiful 

 appearance when polished, so that they were used for 

 decorative purposes by lapidaries before their scientific 

 interest was recognized. 



The members of the Palaeozoic Marattiaceae which 

 have structure preserved generally go by the generic 



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