1897.] The Polyphyletie Disposition of Lichens. 283 
ing of the discriminative powers of certain genera of insects, 
which feed upon lichens, and not upon fungi, Cooke says: 
“ These insects must have come to a sounder conclusion than 
some men, viz., that lichens are not fungi with the addition 
of an innocuous green alga.” 
The most curious error of Reinke’s is made in explanation 
of Moeller’s researches upon Hymenolichenes. The author says 
frankly that after reading Moeller’s article he asked himself 
if its conclusions were contrary to his opinions. At the same 
time, he affords an instructive illustration of how the inter- 
pretation of a fact may entirely controvert its meaning. If 
one were to find a facultative parasite growing at the same 
time on the ground, and upon two different host-plants, the 
explanation would be so obvious that one would not waste a 
thought upon it. The fact that the saprophyte exists along- 
side the parasite, the lichen, would mean simply that here was 
the starting-point of a phylum. Notso with Reinke. To him 
the occurrence of Cora as a facultative parasite signifies that 
here is a fungus, which forms “consortiums” with different 
algee, a proof, as he takes it, that the fungus alone is insufficient 
for the thallus-body. Also, a proof in my mind that a host is 
indispensible to any parasite. As for the occurrence of hymen- 
omycete and hymenolichen together, Reinke considers this en- 
tirely analogous to the concomitant appearance of alga and 
lichen, and, as I have pointed out above, this is true, since it 
involves nothing more than the simultaneous occurrence of a 
saprophyte, its host, and the same saprophyte in the role of a 
parasite. 
I have taken up the above arguments in detail merely to 
demonstrate the little bearing they have upon the question. 
In determining relationships, phylogeny alone has value; his- 
togeny, morphology, and physiology are useful only so far as 
they can furnish data respecting the probable phylogeny. I 
have already said enough to show that I appreciate the exceed- 
ing difficulty of retracing phylogenetic results. Happily, in 
the lichens, the phyletic lines are comparatively short; this is 
especially true in the hymenolichens, where the developmental 
processes are going on before our eyes. On the one side is the 
