MARATTIACEAE 521 



are surrounded by a rather delicate common wall, about four layers of 

 cells in thickness, of uniform structure, and without trace of any annulus. 

 Centrally there is a vascular strand connected with the system of the 

 leaf. The dehiscence appears to have been by terminal pores. The 

 number of spores in a single sporangium was very large : to judge from 

 Renault's detailed drawings it was probably equal to the output of the 

 modern Kaulfussia (Fig. 288). It is evident that the correspondence with 

 this genus was very, close indeed : the plan of the sorus is the same : 

 its form also, for the terminal depression in Kaulfussia is often less 

 marked than is represented in the drawings usually quoted. The two 

 are alike also in the thin parenchymatous tissue of the sporangial wall : 

 in the absence of any indurated annulus, and in the presence of a 

 vascular connection, which I have shown to extend in Kaulfussia also, 

 upwards into the receptacle : 1 though it is not so long or so coherent 

 a strand in the living Fern as in the fossil. The differences are of degree 

 only, and the similarities are most convincing. 2 



Another genus which conforms in type of its fructification to modern 

 Marattiaceae is Scolecopteris. This genus includes plants with sessile or 

 shortly pedunculate sori, of three to six sporangia : they are united 

 below, but separate above, and extended into a more or less elongated 

 beak (Fig. 289 D). The Marattiaceous characters of this fructification 

 are unmistakable, and it has been pointed out by Strasburger 3 that 

 Scolecopteris elegans, Zenk, shows features connecting it with Marattia as 

 regards the form of the sporangia, and with Kaulfussia in their circular 

 disposition in the sorus, while the outline of their upper free portion 

 would point to Angiopteris: in dehiscence it compares with all three, 

 but especially with Marattia. In fact it is a type which unites in itself 

 characters of various living genera. It may be noted that the number 

 of sporangia in the sorus of Scolecopteris is small and variable, but that 

 four and five seem to be the most frequent numbers. 



A genus of very early occurrence, and bearing sori of similar 

 character is Asterotheca : here the three to eight sporangia are in close 

 apposition while young almost up to the apex, but they separate 

 and diverge radially when mature : the peripheral wall is strongly 

 convex, and shows no annulus : the mode of dehiscence was by radial 

 slits (Fig. 289 F). 



1 Studies, iii., Fig. 42, p. 46. 



2 Mr. D. M. S. Watson (Journ. R. Micr. Soc., 1906, p. i) has described a "Fern" 

 synangium from the Lower Coal Measures, well preserved, but detached from the part 

 which bore it. It resembles Ptychocarpus unitus in its synangial state, but differs in its 

 more elongated form, its hollowed apex, and in the vascular* supply being widened into 

 a cup of tracheides : in these latter characters it resembles Kaulfussia. There is no 

 evidence to show . whether it was truly Filicinean or Cycadofilicinean. It is named 

 Cyathotrachus altus. 



3 [enaischc Zeitschrift, 1874, p. 87. 



