3o0 .loiis. noY*: pktehsen 



oii Ihe woodwork, and I should imngine llial llir hrickwork is l)eller 

 able to absorb inoislure (Vom Ihe f^ioiind Ihan llu' woodwork, and 

 relains il willi grcalcr cnergy. I have had niaU-iial t'ioni 4 locahlies 

 (15, 197, 352, 395). 



In all four samples Chlorophycea^ as well as Dialoms were 

 lound. Ihough it is donblfnl whether Ihese had heen alive on one 

 ol Ihe walls (107). Prasiola crispa conslituled Ihe {^realer pari of the 

 Ihree samples (15, 197, 352) The other algæ were Bumilleria exilis, 

 C.hlorella ellipsoidca, Hormidiiim flaccidiini, (Jocijslis rupcslris and 

 Slicbococciis bncilhiris. The Dialoms were chielly represenled by 

 Hanizschid (nnpliioxi/s, Pinniilaria borealis, Naniciila Atoiniis, and 

 .V. iiilrophila. For Ihe remainder of tlie species Ihe reader is rel'erred 

 to the list of the separate samples. 



3. Turf Walls. 



On Ihe turf walls of the old farms a somewhat dilTerenl com- 

 munily of algæ is found. Among the green algæ Prasiola crispa 

 is Ihe c'ommonest, and somelimes Honnidiiim /laccidiini occurs. 

 Resides these I have found a greater or less number of Dialoms in 

 all the samples, Ihey were, however, only represenled by dead fru- 

 slules so Ihat in several instances it was quite impossible for me to 

 find any specimens with cell-contents. Possibly this is due to the faet 

 that the Diatoms struggle hard for exislence liere, so that the greater 

 |)arl of them perish in prolracled periods of desiccation. It may 

 also be Ihal most of Ihe Dialoms have been broughl to Ihe j)lace 

 with the turf which may have been eul in bogs where Ihere is 

 oflen a great degree of moisture. The frecjuent occurrence here, for 

 inslance, of Melosira crennlata here must no doubt be explained 

 in Ihis way. The samples collected from this kind ol" locahly are 

 Nos. 40, 77, 196, 294, 325. 



4. Turf Fences. 



Fences around the »lun« or home lield, are oflen made of piled 

 Unf. From such fences I have collecled a couple of samples (182, 

 381). Il turned out thai Ihey conlained Diatoms and one of Ihem 

 Prasiola crispa. Quite otherwise than on the turf in the house-walls 

 1 found only lerrestrial sjiecies on the fences, especially Hantzschia 

 ainphioxiis, Nanicida Aloimis, X. nuilica, and Pinniilaria borealis. 



The two laller kinds of habilals resemble the ground vcry much 



