PALEOBOTANY — BERRY. 303 



pteris and Tubicaulis, endarch in Botryopteris, with scalariform or 

 reticulate tracheids. In B. forensis the sporangia were pedicellate 

 in groups of from two to six on the ultimate divisions of compound 

 fronds. They were pyriform with walls of two layers of cells and 

 on one side had an annulus several cells in width suggesting com- 

 parison with the Osmundales. The leaf traces vary from rectangu- 

 lar in Granimatopteris and oval in some species of Botryopteris to 

 omega shaped in other species of that genus. All known Botryop- 

 teraceae were small plants thought to have had slightly fleshy 

 pinnules, and abundantly clothed with epidermal hairs. 



The family Zygopteraceae is based largely on a variety of struc- 

 tural remains of petioles, although the stem anatomy and sporangial 

 structure are known in several instances. They range in age from 

 the Devonian (Clepsydropsis) to the Permian. The leaf traces 

 show a variety of complexities of form and histology, and in cross 

 section range from an hourglass or H-shape to the stellate form of 

 Asterochlaena. It seems probable that the elaborate classification 

 which Bertrand has based on the variations of these petiolar strands 

 would not survive a knowledge of the other characteristics of these 

 ancient types. 



The sporangial characters show considerable variation. In Zy- 

 gopteris the sporangia were grouped and annulate much as in Botry- 

 opteris. In Diplolabis and Stauropteris an annulus was not de- 

 veloped; the former had the sporangia grouped in sori or synangia 

 while in the latter they were borne singly on the ultimate divisions 

 of the frond. The class as a whole shows relationships with the 

 Ophioglossales, Osmundales, and Marattiales. 



The Eusporangiate class of ferns comprise two known orders — the 

 Ophioglossales and Marattiales, the former regarded as very primi- 

 tive by most students and but slightly represented in the fossil state, 

 although the Paleozoic Rhacopteris and Ophioglossites and the 

 Mesozoic Chiropteris have often been considered as representing this 

 order. 



The Marattiales, on the other hand, with six existing genera and 

 about 30 large handsome tropical and subtropical species, have an 

 extended geological history. In the present state of our knowledge, 

 confused as it is by the resemblance of Pteridosperm microsporangia 

 to Maratteaceous synangia, it is diffcult to give a satisfactory esti- 

 mate of the relative importance of the Marattiales in the Paleozoic, 

 but they certainly occupied a prominent position in those early floras 

 and this prominence rests on the evidence of the cosmopolitan frond 

 genus Pecopteris, the stem anatomy of the forms referred to 

 Psaronius and its allies, and upon a variety of fructifications. 



The Psaroniaceae were tree ferns sometimes 50 feet or more tall, 

 with fronds, in cases where actual connection has been established, 



