pound state of spinulosa , more resembling the var. dilatata , was 
united with it by Mr. Moore. (See plate 20, the right figure, 
in his ‘British Ferns, Nature-Printed/) To this view I cannot 
readily subscribe, and I only cautiously assented to such a union 
in the last (the eighth) edition of ‘ British Flora.' Immature 
plants of L. uliginosa (especially the middle figure of Mr. Moore, 
Nat. Print., plate 20), do indeed a good deal resemble our N. 
cristatum; but I still think the perfect condition of this plant is 
more allied to our Nephrod. spimdosum than to N. cristatum. It 
would take more space than we can give to notice the various 
views of modern authors on the subject of this and the follow¬ 
ing species of the British Nephrodia , and could not be very pro¬ 
fitable. Every one must form his own judgment in regard to 
the limits of the species, which all must acknowledge to vary 
extremely (less so in regard to the present species) and to be 
pre-eminently difficult of satisfactory determination. 
Plate 17. Fertile frond and stipes of Neph'odium (Lastrea) cristatum, Mich.,— 
natural size. Fig. 1. Scale from the stipes. 2. Fertile segment of a pinna. 
3. Involucre :—all more or less magnified. 
