2 4 



under a high power of the microscope requires a different 

 focus for every minutia of distance. This obliges the 

 operator to use a lower power in order to see the relative 

 distribution of the verrucae, or warts, with which most 

 of the British fern spores are furnished, and which in 

 this case I believe to be a certain diagnostic of each 

 form. In Lastrea pvopinqua the spores are olive-green, 

 not keeled, and covered with minute verrucae equally 

 distributed, so much so that it gives to each the 

 appearance of being simply covered with minute 

 punctures, which ^present the interspaces of the 

 verrucae. In Lastrea filix mas, the spores, which are 

 olive-brown, are keeled, and the verrucae collected into 

 serpentiform markings (or, to give a better illustration, 

 like the spots on the ounce or leopard, arranged in the 

 curved stripes of the tiger). They are also coarser than 

 those on the spores of Lastrea pvopinqua. In Lastrea 

 pseudo mas the spores are olive-brown and obsoletely 

 keeled, and as one would expect to find, very similar to 

 those of Lastrea filix mas, but the eye detects a difference, 

 which consists in the aggregation of the verrucae, being in 

 what (for want of a better name) I have called Hebrew 

 character, or zig-zag marking, as shown on the diagram. 



nth Column. — The localities of each are soon disposed 

 of, Lastrea pvopinqua being solely sub-Alpine, and where 

 found, not a plant of Lastvea filix mas is to be seen, and 

 yet there is abundance of Lastvea pseudo mas. Lastvea 

 Mix mas is universally distributed through the botanical 

 provinces, and Lastvea pseudo mas very commonly so. 



1 2th Column. — Lastvea pvopinqua (not determined). 

 Lastvea filix mas is infected with a disease which 

 disfigures it throughout its growth, but whether the 

 disease is a fungus or the effects of an insect, is as 

 yet not known. Lastvea pseudo mas is so very rarely 

 affected that one may say never. This is again another 

 strong proof of a specific difference. 



