LASTREA TRTSTATA. 229 



of moisture. The habit is upright, and distinct from all other 

 British species. 



Unless under cultivation it is grown in a peaty soil, and 

 in a damp situation, this Fern becomes sickly, and will merely 

 drag on a miserable existence for two or three years, and 

 then die; whilst if nature is copied in its growth, the plant 

 will flourish, and when established in its proper situation, a 

 handsome plant may be obtained. The rhizoma creeps on the 

 surface, sending roots through the moss to the bog below. 

 Owing to the drainage of bosr°rv situations, the Lastrea cristata 

 is becoming more scarce. In the Nottingham locality, (Oxton 

 Bogs,) much drainage has been carried on, and its habitation 

 has been somewhat contracted; but I believe that the proprietor, 

 Mr. Henry Shcrbrook, will respect its present home, and that 

 there is no likelihood of this Fern being exterminated in our 

 county. The locality is an interestinjj one, narrow and wild, 

 with a trout-stream running through it, on the banks of which 

 are many interesting plants, uncommon mosses, and rare insects. 



Fronds erect, narrow, linear-oblong, sub-bipinnate, or bipin- 

 nate, tapering at the apex; pinnae brief and triangular; 

 pinnules oblong, connected at the base, crenato-serrate on the 

 margin. 



Veins forked. Fructification copious, usually occupying the 

 upper half of the frond. Sori circular, numerous, indusiate, 

 and medial. Indusium reniform, flat, and membranous. 



Length of frond from twelve to thirtv-six inches; colour 

 heavy green. 



IxTERRUPTA, Monkmon. — This form, which corresponds with 

 the varieties of Polystichum angular e and Lastrea Jilix-mas, so 

 named, was found by Mr. C. Monkman, in the Malton station, 

 in 1860. Both barren and fertile fronds were well marked. 

 Some years ago I had found similar plants on Oxton Bogs, 

 but they did not' prove permanent, Mv thanks are due to 

 Mr. Monkman for fronds. 



FuRCAXS, Monkman. — From the Malton station. Not uni- 

 formly cleft, and sub-permanent. An interesting furcate variety, 

 equal in size to the normal or type form, but doubtfully 

 permanent. My thanks are due to Mr. Monkman for fronds. 



2 H 



