PTEROPSIDA 119 



no organs that could be called leaves and, for this reason, 

 the plant was placed in the Psilophytales. However, Leclercq 

 has recently discovered abundant remains of the plant and 

 investigations by her and Banks show that there are, in 

 fact, spirally arranged leaves with ^several successive pairs 

 of opposite divisions ; each of the numerous divisions then 

 divides by several successive dichotomies ; the whole appen- 

 dage is arranged in three dimensions'. Some of the leaves 

 were fertile and their ultimate divisions terminated in a pair 

 of sporangia. These workers were, furthermore, able to 

 observe the vascular system of the plant and found that it 

 had a very complex stellate form, as seen in transverse 

 section. Their conclusion, published in a preliminary note,^® 

 is that the genus has more in common with the Cladoxylaceae 

 than with any other group of plants and that it should cer- 

 tainly be removed from the Psilophytales. 



Coenopteridales 



This early group of ferns is a large one, consisting of many 

 genera and species. It showed a wide range of growth habit, 

 for some had creeping stems, others had erect trunks and 

 yet others were epiphytes. As with members of the Cladoxy- 

 lales, here too there is the problem of distinguishing leaf 



Hierogramma type of stele; G, Syncardia type of stele; h, Clep- 

 sydropsis XyxiQ of siQlQ. Pseudosporochnus : i, reconstruction of 

 P. Krejcii. Metaclepsydropsis duplex: J, stem stele; k, petiolar 

 bundle near base ; l, petiolar bundle showing origin of laterals ; 

 M, model showing petiolar bundle giving off laterals. Ankyrop- 

 teris: N, A. Grayii, stem stele and origin of petiolar bundle; o, 

 A. westfaliensis, petiolar bundle. Etapteris: p, E. Scottii, petiolar 

 bundle and origin of laterals ; Q, E. Lacattei, reconstruction of 

 sterile frond; r, E. Lacattei, reconstruction of fertile frond; 

 s, E. Lacattei, sporangia 



(1, aphlebia traces; 2, peripheral loop; 3, branch trace) 



(a-c, I, after Krausel and Weyland; d-h, p, Bertrand; j-l, 

 Gordon; n, Scott; q, r, Hirmer; s, Renault) 



