78 Rhodora [May 
could have been recognized in Linnaeus’s day, nor for a long time 
afterwards. The system of classification adopted by Linnaeus 
for flowering plants remained in general use until superseded by a 
natural system, which in its general outlines and often in considerable 
detail is accepted at present. But all through the nineteenth century 
system after system was proposed for the algae, each practically begin- 
ning anew, the position of genera changing with kaleidoscopic rapidity. 
It is sometimes really pathetic to see with what conscientious care a 
system was developed on what we now know to have been scanty 
material, imperfect data, and misinterpreted observations. Occasion- 
ally we find a piece of work in some limited field of which the records 
have been supplemented rather than superseded by later observations ; 
thus the insight of Vaucher’s Histoire des Conferves, that celebrated 
its centenary four years ago, is little short of marvellous, when we 
consider the scanty appliances then available; Niageli’s Gattungen 
einzelliger Algen of 1848 must be referred to to-day by everyone study- 
ing the unicellular algae; but Nügeli's system, like the systems of 
Kiitzing and the others, was hardly more permanent than last year’s 
snows. Back of the time of C. Agardh, in the earlier part of the last 
century, practically no types are to be found; and though in the 
Agardh herbarium, continued by the son, J. G. Agardh, we have a 
most valuable collection of original specimens, we find in many cases 
that more than one species, as we now know them, was included 
under one name; it was impossible to distinguish them at that day, 
and of course the diagnosis, giving only the characters then discerni- 
ble, gives us little help as to which species should bear the name. 
Evidently the basis that is suitable for the nomenclature of the Rosaceae 
is not suitable for the nomenclature of the Chlorophyceae. 
But is it possible to fix any one satisfactory basis for algae in gen- 
eral? The more we look at it, the less likely it seems. The larger 
algae, those included in the genus Fucus, were fairly well known to the 
older authors, so that nearly all of the species in Turner’s Icones 
Fucorum, 1808-1819, remain valid to-day; but this is by no means 
the case with the species of Dillwyn’s British Confervae of 1809. 
To ignore Turner’s species in the Icones would certainly be un- 
wise; to identify species of Microspora or Oedogonium by Dillwyn 
would be very difficult. ‘Though the idea of different starting points 
for different families of algae may seem at first undesirable, it may 
be the best solution of the problem; a definite proposition to that 
