REPORT ON THE LICHENS OF EPPING FOREST. 
99 
lent eruptions on the upper surface of the thallus of the lichen : 
when the ripe spores of the parasite are dispersed, each eruption 
leaves a white spot in the lichen-thallus. This spot represents 
the medullary layer, exposed by the decay of the algal com¬ 
ponents of the cortical and gonidial layers, which, it is to be 
presumed, the parasitic fungus chiefly attacks. 
Coming now to our List of Additional Lichens recorded from 
the Epping Forest district since the reading of our first paper 
on 5th March. 1909. we have to call attention to the publication, 
in the interim, of Miss A. Lorrain Smith’s completion of the 
British Museum Monograph on the Class 2 ; this important 
work considerably affects the nomenclature of these plants. 
The systematic arrangement adopted by Miss Smith has been 
uniformly followed in the following list, and, in addition, we 
append a supplementary list of those forms included in our 
first paper, the names of which have been altered in the work 
mentioned. 
The number of forms included in the present list is 63, which, 
added to the 46 given in our former list, makes a total of 109 
fully-determined forms. We have again to express our grateful 
thanks to Miss A. Lorrain Smith and to Mr. E. M. Holmes for 
Help in identifying critical forms. 
Family—COLLEM ACE I. 
Tribe—COLLEM EL 
Collema furvum. Ach. 
Several sterile examples, on a flat-topped tombstone in 
St. Nicholas Churchyard, Loughton. 
Family—LICHENACEI. 
Tribe—CALICIEI. 
Calicium melanophseum, Ach., var. ( 3 . ferrugineum. Schaer. 
On oak trunk, Green Ride near Loughton Cam}); fertile. 
C. quercinum, Pers. Tent, f. chlorodes, Nyl. 
On oak trunk between Woodberrie Hill and Green Ride ; 
fertile. 
C. trachelinum, Ach. 
On oak trunk near Debden Slade ; fertile. 
2 A Monograph of the British l.ickens. Part II., by Annie Lorrain Smith, F.I..S., 1911 
