530 BOTANICAL GAZETTE [JUNE 
permeable to acid is shown by the fact that seeds of lemons (which are 
separated from the acid by the walls of the sacs) frequently germinate 
while still in the carpels, though they will not germinate in lemon juice 
several times diluted. 
It seems probable that this condition is a general one in acid tissues. 
The acid and ferment are separated in the tissue probably in a variety 
of ways, but the grinding destroys the separating surface, bringing acid 
and ferment in contact and inhibiting the action of the latter. 
The general effects of acids and alkalies on oxidase ferments are now 
under investigation and will be reported on later.—-G. B. RrEp, Labora- 
tory of Plant Physiology, Harvard University. 
THE TYPE SPECIES OF DANTHONIA 
In a recent paper,’ Professor A. S. Hircucock attempts to show that 
the type species of Danthonia DC. is Avena spicata L. instead of Festuca 
decumbens L. If his arguments are to stand, stability in nomenclature 
will be an impossibility, for they are based purely on personal opinion. 
If a case in which there is doubt as to the type of a genus is to be decided 
on an interpretation of what the author may have thought most repre- 
sentative, it will never be disposed of, for this decision may vary wi 
each succeeding systematist who faces the problem. 
As emphasized at the Vienna Congress, one of - a 
points in nomenclature® “is to aim at fixity of names,” and “in the 
absence of rule” (by which to bring this about) “established cn 
becomes law.” However logical, therefore, Professor H1rcHcock’s 
decision as to the type of Danthonia may be, it is essential for the sake 
of nomenclatural stability that the accepted custom of selecting the 
first species described (when the type is not indicated) be adhered to. 
Otherwise, as pointed out by Professor Hircucock, some other botanist 
may say, “I favor selecting” D. provincialis DC. as the type. 
Now Festuca decumbens is not only the first species described, but 
Professor HircHcocx fails to show that DE CANDOLLE did not consider 
it completely congeneric with his D. provincialis. It is provided with 
an awn, even though rudimentary, and, to quote, “it is evident that 
the author considered the awn to be one of the important distinguishing 
characters of his new genus.” Dr CANDOLLE’s suggestion that Avena 
4 The seeds of all the Citrus fruits examined showed an abundance of oxidases. 
5 The type species of Danthonia. Bort. GAz. 57:328. 1914. 
6 Vienna Rules, 35. 1905. 
