326 Dr. G. Ogilvie on the Vascular 



Lastrea cristata. 



The petiole has two large lateral fasciculi, and three smaller 

 intermediate, the latter running into one upwards ; all with dark 

 sheaths. 



Lastrea Thelypteris. 



The petiole has two flattened and plaited fasciculi, somewhat 

 resembling those of Athyrium Filixfoemina, but with dark sheaths. 

 They unite above into one of a horseshoe section, as in Poly- 

 podium alpestre. 



The rhizome is long, and creeps horizontally. The fasciculi 

 of the vascular cylinder which lie towards the upper surface are 

 thicker than those on the lower. The substance is of pale tissue, 

 with a brown cuticular layer. 



Athyrium Filix fcemina. 



The petiole tapers from a swelling near the base to its point 

 of connexion with the rhizome ; it has two fasciculi, without 

 dark sheaths, which acquire the form of fluted bands, in the 

 dilated portion of the petiole. 



The rhizome is indented as in Polystichum aculeatum, and is 

 formed of pale but dense and thick-walled cells, with a cuticular 

 layer of brown tissue. 



Athyrium fontanum. 



The petiole has two fasciculi running on into the midrib of 

 the frond, without dark sheaths. 



The rhizome has no dark deposit in the parenchyma, but the 

 scalariform vessels have a decided brown tint. 



Asplenium marinum. 



The petiole has a single central fasciculus, without a dark 

 sheath. 



The rhizome is of pale tissue, except the cuticular layer. 



Asplenium Adiantum nigrum. 



Petiole and rhizome as in the last species, except that the 

 former has two fasciculi at the base, which coalesce as they 

 ascend towards the frond. 



Asplenium lanceolatum. 



The petiole has two (or sometimes three) fasciculi, uniting 

 above, as in the last species, without dark sheaths, but with the 

 vessels themselves and the cambium-layer of a brown colour, 

 most decided at the base of the petiole, and disappearing up- 

 wards. 



The rhizome is of pale tissue, as in the last species, except 



