Chroolepus aureus a lichen 



Albert Schneider 

 (With plate 22) 



During my study of the lichen formations in the vicinity of the 

 Minnesota Seaside Station (near Port Renfrew,. Vancouver Island, 

 B. C), I frequently found Chroolepus mirens (L.) Kutz. [7>r;/- 

 tepohlia aurea (L.) Mart.j on trees (spruce and hemlock) and on 

 rocky ledges overhanging the beach. It is exceedingly abundant 



m certain circumscribed areas and shows great variability in the 

 length of filaments. There was also observable a marked differ- 

 ence in color, varying largely between that of old gold and a 

 bright orange-brown. As to whether the difference in color indi- 

 cated two distinct species I will not venture an opinion at present, 

 although the indications are that that is the case. It is very essen- 

 tial that these plants should be studied in the fresh state as they 

 lose the characteristic color very quickly when placed in the her- 

 barium, w^hich increases the difficulties in the way of identification. 

 The representatives of the genus Chroolepus are especially 

 interesting because of their tendency to associate themselves 

 biologically with fungi to form lichens. Chroolepus wnbrimis (rep- 

 resented in thirteen lichen genera), or a species closely similar to 

 it, forms the algal symbiont of many lichen species. Bearing this 

 in mind, a more careful study was made of C. aureus, to determine 

 if this plant presented this character to any marked degree. Fresh 

 material, obtained from ledges of overhanging sandstone and from 

 trunks and branches of hemlocks, was carefully examined under 

 the microscope. The normal filaments showed a variation in 

 length as shown in plate 22, The cells contain numerous reddish- 

 brown granules or globules. Very frequently there was found a 

 twining hyphal fungus, especially abundant about the bases of the 

 filaments. This fungus was, howev^er, not sufficiently constant in 

 its appearance to w^arrant the assumption that it represented a 

 marked biological association with the alga, either antagonistic or 

 mutualistic. More likely it represents merely an accidental asso- 

 ciation, due to the fact that both organisms live upon the same 



431 



