MATONINEAE 



567 



Sporangia in which the annulus is not tilted are shown in Figs. 317 A, c; 

 from these it will be seen that the annulus starts close to the stalk; it 

 first curves downwards towards the basiscopic side of the sporangium, 

 then circling round it, curves upwards, the highest point being reached 

 at the distal end of the sporangium ; passing this it again curves down 

 wards towards the basiscopic side, and stops short at some distance from 

 the stalk ; it is at this point that the dehiscence takes place, but though 

 the cells immediately beyond the end of the annulus may show some 

 regularity of division, there is in Matonia no highly specialised stomium 

 as is the case in most Leptosporangiate Ferns. Fig. 317 (the central 



FIG. 317. 



Malonia. pectinata. A, , C and the central figure represent the mature sporangia in 

 various aspects. ,F=young sorus ; /, z = indusium ; s = sporangium. _= sporangium 

 with cap-cell; = acroscopic, b = basiscopic side. D = sporangium with tapetum 

 doubled. A-Cx$o. D-Fx.2oo. 



figure) shows the rupture ; x it also shows a case of the annulus stopping 

 short of the stalk on either side, and that there is not here any 

 continuous series of non-indurated cells, such as that seen in Loxsoma. 



Thus Matonia has a sporangium with a short and massive stalk and 

 a large head, in which the annulus is not of a highly specialised, nor 

 even of a constant type, though in its main features it corresponds to 

 that of the Gleicheniaceae. It differs here, however, in its variability, 

 its lateral dehiscence, and in the comparatively small output of spores. 



Of the fossil Matonineae the sori are best known in Laccopteris, which 

 is practically identical with Matonia in the size, disposition, and structure 

 of the sporangia and spores, but differs in having apparently no indusium 

 (Fig. 318). Probably, however, the sori of Matonidium and of Microdictyon 



