CYSTOPTEEIS. 103 







Among other names, this plant has borne those of Asple- 

 nium Ceterack, Scolopendrium Ceterach, Grammitis Ceterach, 

 Notolepeum Ceterach, and Gymnogramma Ceterach. 



Genus VI. CYSTOPTERIS, Bernhardi. 



THE species of Cystopteris are all small, fragile Ferns, yet, 

 notwithstanding, they are very beautiful and very interesting, 

 and furnish some remarkable differences of form. They are 

 much more delicate and herbaceous in their texture than the 

 majority of our native species, and hence are well adapted 

 for the purpose of minute investigation into the nature of 

 their venation and fructification. Their texture alone almost 

 suffices to tell a practised eye their family position, but the 

 tyro needs a more precise characteristic, and this is found in 

 the structure of the scale or indusium which covers the sori. 

 The sori in these plants are round, as in Lastrea and Poly- 

 stichum, all, equally with Cystopteris, once included under 

 the old family name of Aspldmm ; but here, instead of being 

 almost flat and circular, the indusium is inflated or bulged 

 out like a hood, and is attached at the back (towards the 

 base of the pinnule) of the sori by its broad base, covering 



