Fink: Classification of Lichens 
109 
stood so long as we confine attention to the higher foliose or fruti- 
cose lichins or even to higher crustose forms. 
De Seynes (122, 123) found specimens of Sclerotinia tuberosa 
(Hedw.) Fuck., the hymenial surface of which showed produced 
ends of paraphyses closely applied to unicellular algae. The re- 
sults were fully published in 1886, and the figures show that in 
some instances branching, haustorial elongations of three or more 
paraphyses are closely attached to a single algal cell. The alga 
is said to be Chlorococcum hiimicola, which occurs with lichens so 
commonly. The swollen and turgid haustoria are cut off by a 
septum and are like those of typical lichens which live with the 
same alga. But few of the paraphyses are attached to the algal 
cells. This observation has not been repeated, and the relation 
of this fungus to the alga is rare and accidental ; yet it illustrates 
the manner in which lichens arose from non-algicolous fungi. 
Our view of lichens can be construed to make the rare Sclerotinia 
individual which lives with the alga a lichen ; but this may better 
be left to personal judgment. The point regarding the origin of 
lichens and their relationship to other fungi is as well shown 
whether we regard these individuals lichens or not. 
Archer (3) described and figured lichen apothecia on Scy- 
tonema myochrous, Sirosiphon alpinus, S. pnlvinatus and Stig- 
onema mamillosum. The spores are much alike in all of these 
and strongly resemble those of our Ephebe pubescens (L.), Fr., 
though not the same. He thought perhaps that the lichen was the 
same on all of these algae, but his spore measurements would 
indicate otherwise. He found neither hyphae nor sexual organs ; 
but it is very probable that he observed one or more primitive, 
facultative lichens. 
Frank (58) found that Arthonia radiata (Pers.) Ach. grows 
within the periderm of trees, often for years, wholly outside the 
relation with the symbiotic alga, Trentepohlia umbrina, and that 
some individuals never parasitize the algal host at all. After a 
time, according to Frank, some of the algae bore into the peri- 
derm and are attacked by the lichen, which now grows more luxur- 
iantly, penetrates deeper into the periderm, becomes also partly 
superficial and produces apothecia. Those individuals that fail 
to enter into the partnership with the alga do not produce apothe- 
