HYMENOPHYLLACEAE 



579 



later may be correlated with the close packing of the sporangia in the 



sorus. The view of the sporangium from the side on which dehiscence 



takes place shows that the annulus is not < 



continued throughout as a distinct series 



of cells (Fig. 325, No. 96); but there is no 



definite group of cells of the stomium ; this 



feature is again comparable to that in Gl. 



circinata. The drawings of the central and 



peripheral faces (Fig. 325, Nos. 97, 98) will 



complete the knowledge of the external form 



of the sporangium in this species. The 



stalk is short and rather thick, and the 



insertion is by a rosette of cells, some six in 



number. 



For comparison with the sporangium of 

 Hymenophyllum^ that of Trichomanes, radicans 

 is represented in Fig. 325, Nos. 99-102, as seen 

 from four different points of view. No. i o i 

 shows the sporangium presenting its central 

 face ; the close analogy with No. 97 of Hym. dilatatum is obvious, though it 

 is smaller in size, and with fewer cells in the annulus ; but fluctuations less in 

 extent though similar in nature are found in Tr. radicans itself, the cells of 



FIG. 324 bis. 



Hymenophyllum Wilsoni, Hk. Sorus 

 in longitudinal section showing the 

 receptacle with divisions indicating inter- 

 calary growth, and the first sporangia 

 originating near the apex, x 100. 



FIG. 325. 



Nos. 95, 96, 97, 98 = Sporangia of Hymenophyllum dilataiitui. Swart/, seen n-spi-i i ivd\ 

 from the two sides (Nos. 95, 96), and from the central (No. 97), anil peripheral (No. 98) 

 faces. Nos. 90, 100, 101, I02 = similai lit,'int;s, to the same scale of l'>i,htnanes 

 radicans, Swam. Nos. 99 and 100 show the lateral views. No. 101 shows the central, 

 and No. 102 the peripheral faces. All X 50. 



the annulus varying between 20 and 25. There is also a greater simplicity in 

 the region of the stomium, which in Trichomanes is represented by two cells 

 only. No. 102 represents the "peripheral" face, the thin-walled region being 

 surrounded by the annulus, which takes the form of a twisted hoop. This 

 twisted form is clearly shown in No. 99, which demonstrates also the relation 



