ADDENDA. 
The following additions have become necessary while 
this edition has been going through the press : 
Page 50, under POLYPODIUM ALPESTRE, insert : 
P. flexile, (Pseudathyrium, Newman.' Newm.) " Ha- 
bit lax flexile. Frond strap-shaped spreading horizontally, 
8-18 in. long, bipinnate ; pinnae distant throughout, hori- 
zontal or drooping, subobtuse ; pinnules 7-10 on each side 
of midrib of pinnae, narrower at base, distant, subobtuse ser- 
rated; clusters of capsules 6-8 on each pinnule, distant, 
always separate. On micaceous rocks at the head of 
Glen Prosen, Clova Mountains, Forfarshire, Mr. J. Back- 
house" (Phytol. iv., 974). 
P. alpestre is said to differ from this plant in being 
of a rigid habit; and in having suberect lanceolate fronds, 
with ascending subacute pinnae distant near the base 
but elsewhere crowded ; the pinnules wider at the base 
crowded and numbering 25-35 on each side the midrib 
of pinnae, twenty-five or more clusters of capsules being 
borne on each pinnule, these clusters crowded and finally 
confluent. I am not sufficiently acquainted with P. 
flexile to form an opinion as to its distinctness, but I 
fear the differences pointed out only indicate a form of P. 
alpettre, influenced by tke conditions of the locality which 
has produced it, the peculiarities having perhaps acquired 
the value of a permanent variation. 
Mr. Backhouse informs me that the peculiarities of this 
plant are not the result of shade, as it was found growing 
in less shady situations than those in which the ordinary 
form of P. alpestre was met with. 
Page 62, under GYALSOGRAMMA LEPTOPHYLLA, insert: 
The spontaneous occurrence of this fern in Jersey is 
confirmed. It appears to be a true native of the island, 
