Archer — On a Minute Nostic loith Spores. 311 
I would explicitly deprecate any supposition that the observation 
was founded on any m<^re isolated filament, met with in the same 
material as the rest of the ordinar)^ examples of this Nostoc around, 
and assumed by me to have emanated from some of them, and, there- 
fore, possibly that of some other genus. The filaments were not iso- 
lated, but, contorted about in quite the ordinary way, were still in- 
volved in the parent matrix, which was bounded by the distinct pellicle, 
or " periderm," generically characteristic, and in all respects, save the 
remarkable speciality described, this example was absolutely the same 
as the others in the same gathering ; in fact, the little Nostoc was in- 
tact. It might be said, possibly, this little plant was rather a Monor- 
mia, but the definite periderm to the rounded fronds places a bar to the 
assumption, and I do not think any observer would see it and pronounce 
it other than a N'ostoc. 
In making a drawing for illustration, it is of course unnecessary to 
present more than one spore, with its adjacent heterocysts and a few 
cells of the filament. To give the total frond, and its long, tortuously 
looped and curved filaments, with their numerous spores and heterocysts, 
and to convey an idea of the matrix, with the bounding periderm, would 
have been an unnecessary labour and expense, and to carry it out on 
the scale of some 400 diameters would have occupied a very consider- 
able space. 
I would now advert to Professor Heess's views, as given in his me- 
moir above alluded to. This observer is an adherent of the hypothesis 
already propounded by Professor Schwendener, as regards the nature of 
Lichens, who, in his turn, seems possibly to have had suggested to him 
the working out of some such idea as he has arrived at, by the alterna- 
tive conclusion put forward by Professor de Bary, as one or other 
being a necessary outcome or result deducible from the existent know- 
ledge of the gelatinous Lichens (Gallertflechten) or the Collemaceae 
and allies, and seemingly embracing also Ephebe in his generalisation. 
This the latter thus enunciates — '^Either the Lichens in question are 
perfectly developed states of plants whose imperfectly developed forms 
have hitherto stood amongst the Algae as the J^Tostocacese and Ohroococ- 
cacese. Or the I^'ostocacese and Chroococcacese are typical Algae — they 
assume the form of Collema, Ephebe, and so forth, through certain para- 
sitic Ascomycetes penetrating into thsm, spreading their mycelium into 
the continuously-growing thallus, and frequently attached to their 
phycochrome-containing cells."^' The former of these hypotheses, as is 
well known, has many supporters, and, seemingly, a considerable 
amount — at least, in certain instances — of evidence in its favour. The 
latter hypothesis, on the other hand, has found, if fewer, even more 
staunch adherents, most prominent amongst whom are Schwendener 
and Heess. 
* Professor A. de Bary: "Morphologie u. Phys d. Pilze, Flechtenund Myxomy- 
ceten" — ia Hofmeister's " Handbxich der phys. Eot.," Bd. ii., p. 291. 
