THE EVOLUTION OF PLANTS 



593 



After investigations extending over nearly 90 j'cars, "we 

 are now in position to draw a fairly complete picture of 

 the plant as it must have appeared when living. 



"It was in effect a little tree-fern, with long, slender, 



Fig. 415. — Lyginodetidron old ha mi urn. Pinna of a microsporophyll, 

 found in an ironstone nodule. Before its identitj' was established this 

 specimen was named Crossotheca Hoeninghausi. The somewhat pellate 

 fertile pinules on the ultimate branches, bear each a fringe of micro- 

 sporang^ about 3 mm. long. The appearance has been likened to that 

 of a fringed epaulet. (After Scott, from a photo by Kidston.) 



sometimes branched, stem, 4 centimeters or less in diame- 

 ter, and provided with spines b}- means of which it 

 probably climbed on its neighbors. The foliage was dis- 

 posed spirally and consisted of relati\ely very large, finely 

 38 



