276 NOTES. — ORIGINAL AND SELECTED. 



with several sorts of shell-fish, as oysters, mussels, cockles, buntins, crabs, 

 prawns, red and white shrimps, craw-fish, &c, are there to be caught below 

 bridge in the river of Thames. 



To-day, of course, Thames salmon and oysters have long 

 been, to a large extent, things of the past. — W. W. Glenny, 

 Barking. 



BOTANY. 



Ricciella fluitans in Epping Forest. — This interesting 

 little Liverwort was growing luxuriantly last autumn in one of 

 the ponds on Golding's Hill, Epping Forest. The fronds are 

 dichotomous, narrow, strap-shaped, and from half to two inches in 

 length. The allies of this genus are usually found on damp soil 

 or stones, though some species are able to withstand drought. 

 The terrestrial species have numerous air spaces on the upper 

 surface of the fronds, and bear root-hairs and thin green scales 

 on the lower surface. Ricciella fluitans is usually submerged in 

 water, though some individuals are to be found growing on the 

 mud around the margin of the pond. The air spaces are 

 completely roofed over in the aquatic form, but in the case of 

 plants growing on land, the air spaces are not completely 

 closed and communicate with the external atmosphere by means 

 of a small pore. There are no root hairs, and only very small 

 scales in the aquatic forms, but these structures are developed 

 considerably when the plants are transferred to a solid sub- 

 stratum. The fronds also become broader and shorter. The 

 floating plants are sterile. 



I am indebted to Mr. W. H. Pearson for confirming the 

 name of the species. — Henry Whitehead, Essex Museum of 

 Natural History. 



Birch-tree Disease. — The disease, which destroyed so many 

 birch-trees, and was so prevalent during the years 1899-1902, 

 has almost entirely disappeared in the forest area. One now 

 very rarely meets with a dead birch. The decline was almost as 

 sudden as the outbreak, for although during the last three 

 years some few trees were attacked, the injury done was not 

 great and the trees slowly recovered. 



As far as I have been able to observe these remarks apply 

 equally to the other localities mentioned in the report in the 

 disease affecting the birch trees in Epping Forest and elsewhere 

 (Essex Naturalist XL, 273). — Robert Paulson. 



