312 
Proceedings of the Royal Irish Academy. 
Ilelin([uisliing the opinions supported by him in the earlier portions 
of his elaborate memoir on the Lichen- thallus,"^' Schwendener, before 
he concludes, propounds the doctrine that not only are the Lichens" 
in question (the Collemaceae, alluded to by de Bary) no Lichens," but 
that the whole class, without exception, falls under the same category ; 
that is to say, that each is to be regarded as some one or other Algal- 
type which has become, as it were, the home or residence of a parasitic 
growth — the combination of the two being, in point of fact, the so- 
called Lichen. His views on the question the author has given more 
at large, in relation to various types, in a subsequent memoir.f These 
he states generally thus: — "As the result of my researches all these 
growths [Lichens] are not simple plants, not individuals in the ordi- 
nary sense of the word; they are rather colonies, which consist of 
hundreds and thousands of individuals, of which, however, one alone 
plays the master, whilst the rest, in perpetual captivity, prepare the 
nutriment for themselves and their master. This master is a fungus of 
the class of Ascomycetes, a parasite which is accustomed to live upon 
others' work ; its slaves are green algae, which it has sought out, or 
indeed caught hold of, and compelled into its service. It surrounds 
them, as a spider its prey, with a fibrous net of narrow meshes, which 
is gradually converted into an impenetrable covering ; but, whilst the 
spider sucks its prey and leaves it lying dead, the fungus incites the algge 
found in its net to more rapid activity — nay, to more vigorous increase. 
... If this mode of illustration be permissible, this fungus forms a 
remarkable contrast not only to the predatory and murderous spider, 
but, in quite an analogous way, to the vine and potato-fungus, as well 
as all other fungi which vegetate in living organisms, and destroy their 
host-plant, or host-animal, in the unequal struggle. ";]: Such, popu- 
larly" expressed, is Schwendener' s view as to Lichens" at large, 
which he now holds and supports. This quotation, I would venture 
to suggest, would seem sufficiently to convey its own refutation of the 
hypothesis, inasmuch as this assumed parasitic fungus does not destroy 
or live upon its assumed algal-host. If the parasite" cannot be a 
''fungus" it must be something else — that something else no more nor 
less than the veritable "lichen," though it may be, indeed, but in part 
represented; though, of course, on all hands it is agreed that Lichens 
and Fungi, save the gonidia, have between them no absolute line of 
demarcation. 
Seemingly, at first, more impressed with the applicability of 
Schwendener's hypothesis to the Collemaceae, though he no doubt after- 
wards accepts its complete tenability as regards the whole class of the 
" Lichens," Eeess conceived the idea of "sowing" the spores of Collema 
* Dr. S. Schwendener — Untersucliungen ueber den Flechten-thallus," in Prof. 
Nageli's " Beitrage zur wissenscli. Botanik," Hft. 4, p. 195 (1868). 
t Dr. S. Schwendener — " Die Algentypen der Flechtengonidien," Basel, 1869. 
Schwendener — "Die Algentypen," etc., p, 3. 
