64 



It is not at all easy to cultivate this fern successfully : it is too 

 impatient of confinement to live long in the greenhouse, and the 

 cold frame, so useful for the protection of other half-hardy species, 

 is almost certain death to this. The metropolitan cultivator is told 

 that London air disagrees with it, and yet the only plant of it I 

 possessed in my early career, lived in a nook of an old wall, in a 

 back area in Hatton Garden, for several years, and may be there 

 still, unless eradicated by repair ; sun never reached it, and ancient 

 mortar, which, constantly moist, had somewhat the consistence of 

 paste, probably agreed with its constitution ; a very necessary point 

 to be studied in planting, as when left to its own selection, or in 

 the wild state, it seems universally to prefer a calcareous habitat. 

 Whether planted in the open fernery, or grown in pots, great care 

 must be exercised as to drainage, and in the latter case especially to 

 avoid wetting the fronds in watering. 



Genus 10. BLECHNUM. 



GEN. CHAR. Sori forming a continuous line on each side of the 

 mid-vein, and parallel to it : covered with a continuous indu- 

 sium opening inwardly. 



Named from the Greek, /3X^%vov, applied to the following or 

 some other species of fern. 



The arrangement of the fructification is very peculiar in this 

 genus, and is dependent upon an equally characteristic form of 

 venation, which latter, however, being in most instances very ob- 

 scure, I have omitted from the generic character. The lateral veins 

 are alternate, and extend, in our British species, obliquely upward 

 about half-way towards the margin, when, by a sudden turn, each 

 runs parallel to the mid-vein and anastomoses with the one above it, 

 thus forming an apparent longitudinal vein on each side of the 

 middle one. The sori occupy the upper or inner sides of these 

 lateral veins, from the bend to the point of contact with the next, 

 and thus become blended into an uninterrupted line, which the 

 cont inuity of their indusia renders more decided. 



BLECHNUM BOREALE. Hard Fern. TAB. XXXVII. 



Fronds linear-lanceolate, of two forms: fertile ones erect, pectinate- 

 pinnate, with distant, narrow linear acute pinnas: barren ones spread- 

 ing, pinnatifid, with broadly linear blunt approximate lobes. 



Blechnum boreale, Swartz. Smith. E. B. 1159. Babington. Hooker 

 and Arnott. Blechnum spicant, Roth. Withering. Moore, 

 Handb. Newman, Hist. Brit. Ferns. Osmunda spicant, 

 Linnaeus. 



Very common in almost every part of the kingdom, on heaths 



