122 
latioii and found that many species had been separated 
from it and that the rest could establish a proper genus 
upon good, partly new, characters. Many old names 
have in this manner been maintained, but with chan¬ 
ged characters at different times, other names of he¬ 
terogeneous genera have been abandoned^ because their 
characters had not been modified little by little. For 
what reason Lagerheim did not approve of reviving 
the name Trihonema^ he has not mentioned. 
I cordially agree with Hazen’s opinion that 
Linné could not ”distinguish the numerous filamen¬ 
tous forms known to us only by the use of good 
microscopes”, and I do not insist upon the preserva¬ 
tion of the name Conferva owing to its being a genus 
in Linné’s Spec. Plant. 
Hazen says that there is a moderately strong 
argument in favor of employing the name Conferva 
for the genus Rliizoclonium if it is to be retained at 
all in modern algology” — —, because the first spe¬ 
cies mentioned in Linné’s Spec. Plant, ed. 1, Conf 
rividaris^ probabl}^ belongs to Rhisoclonium. He holds 
the american ~ opinion that the first s^^ecies (in the 
order) is the type of the genus and must follow the 
old genus name at the dividing of the genus. But 
neither Linné nor the old authors had such a rule. 
In Linné’s Philosophia botanica § 246 runs thus: 
”Si genus receptum, secundum jus naturae (162) et 
artis (154), in plura dirimi debet, tum nomen antea 
commune manebit vulgatissimae et officinali plantae.” 
— How does Hazen apply his rule? The type of' 
Microspora is M. floccosa (Vauch.) Thur., he says 
(1. c. p. 168); now it is not.first in the order, but 
the fifth in his descriptions. Why is not the ”type” 
always the first in the order, if the place has such 
a decisive importance? 
Hazen says 1. c. p. 182: ”The fact that Linnæus 
described onlj" two unbranched species” (of Conferva 
