INTERRUPTED FERN. CLAYTON'S FERN. 



Osmunaa claytoniana L. 



VERY large, coarse ferns, tlie tallest leaves fertile in tKe 

 middle. Fronds oolong-lanceolate, tKe fertile mucK 

 taller than tKe sterile. Pinnae otlong-lanceolate, deeply cut 

 into numerous otlong blunt entire segments, without wool at 

 the tase. Two to five pairs of the middle pinnae on the 

 fertile fronds spore-oearing, very much contracted, completely 

 divided, densely cylindric, dark green at first, finally hrown 

 and withering. Spore-cases large, glohular, naked, opening 

 hy a longitudinal slit. Fertile leaves fometimes five feet tall, 

 erect, curving at the top, surrounded by the shorter sterile 

 leaves. Blades smooth, with forked veins, turning yellow- 

 in fall. Stems yellow, arising in a cluster from a stout root- 

 stock. 



This IS the largest fern in the Dells and a very common 

 one in the open ravines. The common name, interrupted 

 fern, refers to the position of the fruiting pinnae on the 

 middle of the fertile leaves. This character readily dis- 

 tinguishes it from the other large ferns of the same general 

 form, the cinnamon and the ostrich. 



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