ON THE LICHEN-GONIDIA QUESTION. 
271 
far are what are called algae, according to the turbid hypothesis 
of Schwendener, from constituting true algae, that on the con- 
trary it may be affirmed that they have a lichenose nature, 
whence it follows that these pseudo-algae are in a systematic 
arrangement to be referred rather to the lichens, and that the 
class of algae hitherto so vaguely limited should be circum- 
scribed by new and truer limits.” In this last observation 
there no doubt lies a complete answer to the above considera- 
tion adduced by Schwendener in support of his theory. Hence 
such so-called algal genera as Cora , Fr., Dichonema , N. ab 
Esnb., Scytonema , Ag. (= Gonionema , Nyl.), Sirosiphon , 
Kutz (= Spilonema , Born.), and probably some others are 
as yet known only in a very imperfect condition. This, as 
will at once be perceived, would very considerably reduce the 
lists given by Schwendener and Bornet ; and if it be conceded 
(nor can it reasonably be denied) that some other algal genera 
are but free living lichen-gonidia, these lists would clearly 
dwindle down to nothing. Such a solution of the, in some 
cases real , and in others only fancied , identity of certain sup- 
posed algse with lichen-gonidia, is certainly much more natural 
and intelligible, even as it rests upon surer grounds, than the 
forced and prima facie most improbable Schwendenerian theory. 
As a very striking example of this fancied identity, which after 
all is only “similarity,” let us take one of Bornet’s strong 
points, viz. the identity of Protococcus viridis with the gonidia 
of Physcia parietina , for this is evidently what he wishes to 
be inferred from his culture experiment. The two are no doubt 
very similar , but a reference to our Plate, figs. 3 and 4, will 
suffice to show that they are not identical ; for, as will be seen, 
the gonidia of Physcia parietina are larger, and multiply 
themselves in a lesser degree, while the Protococcus multiplies 
itself with the utmost readiness and celerity, much more 
quickly indeed than do the gonidia. Ex uno disce omnes . So 
much, then, for the first of the two main considerations by 
which Schwendener seeks to support bis hypothesis. 
We turn, therefore, to the second of these, viz. the relation 
between the gonidia and the hyphse. Here he affirms, “ That 
as yet the genetic relationship of the gonidia to the hyphse has 
nowhere been directly proved, but only assumed for anatomical 
reasons,” whilst, as he adds, “ the anatomical connection itself 
may possibly depend on 6 copulation.’ ” Now, it is worthy 
of notice that this assertion is directly at variance with what 
Schwendener himself originally believed, and which he sup- 
ported by figs, in Naegeli, “ Beitrage zur wiss. Botanik,” 
Heft, ii., p. 125, t. i. f. 18, t. v. f. 6. This view, he thought, 
was sufficiently established by the previous observations of 
Bayerhoffer and Speer schneider, though he maintained that the 
