Fructification. 



33 



the midvein. In some species part of the indusia are double. The 

 veins are free in all our species. In Euasplenium the sori are 

 straight or slightly curved ; in Athyriom they are often curved, 

 even horseshoe shaped and frequently cross to the outer side of 

 the fruiting vein. 



49. Scolopendrium (Fig. 9), 

 bears the linear sori in pairs, one 

 from the upper side of a veinlet 

 and its mate from the lower side of 

 the next. The indusia are attached 

 by their edges to the veins, and 

 folding toward each other appear 

 like a double indusium covering 

 a single sorus. The veins extend 

 nearly at right-angles to the mid- 

 vein, are free and usually forked. 



so. Camptosorusl The walk- 



, r 1 11 1- . Fig. 9. Scolopendrium vulgare, 



mg-leaf has oblong or hnear m- g^ section of frond showing vena- 



dusiate sori, which are irregularly tion and fructiiication. (Original.) 



scattered and' borne partly on veins parallel to the midvein, and 

 partly on those that are oblique. Those near the midvein are sin- 

 gle, those toward the margin are often approximate in pairs and 

 often form crooked lines. The veins are everywhere copiously 

 reticulated. 



51. Phegopteris. — In this genus the sori are round and naked 

 as in Polypodium with which this genus is sometimes united. 

 The sporangia spring from the back of the veins instead of the 

 apex as in the latter genus and the veins are free. 



52. Aspidium is largely represented in our limits by two well 

 marked sections which are sometimes regarded as distinct genera, 

 and a third section with characters less distinct containing a sin- 

 gle species. In all the sori are roundish and borne on the back 

 of the veins or rarely at their apex. In Nephrodium the indu 

 sium is cordato-reniform or orbicular with a narrow sinus. This 

 at first covers the sorus and is attached by its margin, but later 

 busts away at the margin but remains attached at the sinus. In 

 some species in this section the indusium becomes shriveled be- 

 fore the fruit matures and in this condition might be mistaken for 

 a non-indusiate species (Fig. 10). 



In PoLVSTicHUM the indusium is orbicular and peltate being 

 fixed by the centre ; the veins are free as in Nephrodium (Fig. 11). 

 -5 



