BOTANY 



(A. i)iride) is found on Falcon Glints and abundantly in Harthope and 

 Ireshope in Weardale. The sea spleenwort (A. marinum), once plentiful 

 on the magnesian limestone cliffs, is now only to be found in the most 

 inaccessible places. The brittle-bladder fern (Cystopterisfragilis) grows at 

 Castle Eden Dene, and flourishes wherever sufficient moisture can be 

 obtained on the limestone rocks in the upper valleys of the county. 

 The hard fern (Lomaria Spicant) is very widely distributed, and especially 

 abundant on the hills and edges of the moors, ascending to the highest 

 points. The moonwort (Botrychium Lunaria) cannot be said to be rare in 

 Durham. The writer has found it at an altitude of 1,700 feet on the 

 flanks of Kilhope Law, and it may frequently be noted in Burnhope, 

 Rookhope, and Langdon Dale. The adder's-tongue (Ophioglossum 

 vulgdtum) is also widely distributed, ascending to 1,300 feet, where the 

 writer found well-grown specimens near the black shales in Burnhope. 



Among the Equisetacea (horse-tails) eight species are recorded. 

 The beautiful Equisetum maximum is not uncommon in the woods on the 

 river banks, descending to the cliffs of magnesian limestone near Black- 

 hall Rocks, and in Castle Eden Dene it forms a veritable forest of green 

 umbrageous growth. E. arvense, commonly known as the 'paddock pipe/ 

 is freely dispersed, and gives rise to considerable trouble by reason of its 

 long, creeping rhizomes entering and blocking up the deep field drains. 

 The graceful E. sylvaticum ascends to 1,600 feet in Harwood, and is met 

 with in all the damp woods. E. variegatum, E. Jimosum, and E. palustre, 

 are also widespread, the latter reaching 2,100 feet on Highfield ; E. 

 byemale occurs more generally on the lower ground in boggy woods. 



Of the Lycopodiacea (club-mosses) the three species of Lycopodium 

 the stag's-horn moss (L. c/avatum), L. alpinum, and L. Selago are found on 

 the highest fells, while the tiny Selaginilla Selaginoides grows commonly in 

 the upper parts of Weardale and Teesdale, and at one time found a home 

 on Gateshead Fell. 



LIST OF FERNS AND FERN ALLIES 



ORDER FILICES 



Tribe II. Polypodieai. 

 Pteris aquilina, L. 

 Cryptogramme crispa, Br. 

 Lomaria Spicant, Desv. 

 Asplenium Ruta-muraria, L. 



Trichomanes, L. 



viride, Huds. 



marinum, L. 



Adiantum-nigrum, L. 

 Athyrium Filix-fcemina, Bernh. 



var. molle, Roth. 



rhzticum, Roth. 

 Scolopendrium vulgarc, Sm. 

 Woodsia ilvensis, Br. 

 Cystopteris fragilis, Bernh. 

 Aspidium Lonchitis, Sw. 



aculeatum, Sw. 



angulare, Willd. 

 Nephrodium Filix-mas, Rich. 



ORDER FILICES (continued) 

 Nephrodium cristatum. 



spinulosum, Desv. 



dilatatum, Desv. 



a-mulum, Baker. 



Oreopteris, Desv. 

 Polypodium vulgare, L. 



Phegopteris, L. 



Dryopteris, L. 



calcareum, Sm. 

 Tribe III. Osmundae. 



Osmunda regalis, L. 

 Tribe IV. Ophioglone<e. 

 Ophioglossum vulgatum, L. 

 Botrychium Lunaria, Sw. 



ORDER EQUISETACE.* 



Equisetum arvense, L. 



maximum, Lamk. 



pratensc, Elirh. 



61 



