TRIBONEMA 183 
nema Derbes & Solier (1856). This genus was based on a single 
species, Conferva bombycina, and in the diagnosis, for the first 
time in the history of the species, explicit mention was made of 
the most essential character, namely, the form of the chromato- 
phores, although it had been previously suggested in the plates 
of Kützing. The method of zoospore dispersal was also first 
described and illustrated by Derbes & Solier. There is, then, 
every reason for employing the name Tribonema as a memorial of 
the discernment of these authors. 
Only a small number of forms is known to belong in this 
genus, and the inclusion by DeToni of a long array of species of 
Conferva and Psichohormium in the genus Conferva as emended 
by Lagerheim, is quite unwarranted. Probably many of these 
ought to be reduced to synonymy or placed on the list of indeter- 
minables ; certainly very few of them have been shown to possess 
the characters of the revised genus. The evil results of De- 
Toni’s wholesale grouping of species of ill-defined character may 
be seen in the very unreliable determinations of species by certain 
American writers who seem to have pinned their faith to his work. 
(See “ doubtful forms” under 77zbonema and Microspora.) 
There are indications in Lagerheim’s work that he contem- 
plated reviving the name Tribonema, but apparently a too conser- 
vative instinct deterred him from abandoning Conferva. 
There is very little doubt that the action taken by Borzi,* 
and supported by Bohlin, Blackman, and Wille, in removing this 
genus from the Ulothricaceae is entirely justified. The structure 
and composition of the cell-wall, the character of the chlorophyl, 
and the absence of starch all point to the close affinity of 7772o- 
nema with the Ophiocytiaceae. 
As noted in the introduction, however, for present expediency 
in bringing into American literature, which has sadly confused 
Microspora and Conferva, the striking differences between these 
genera, the older arrangement has been here retained. Doubtless 
the easier course would have been to omit the genus, since some 
* Borzi, A. Boll. Soc. Ital. Mic. 1: ہے‎ 1889. 
Bohlin, K. Bih. Kong. Svensk, Vet.-Akad. Hand. 233: No. 3. 1897. 
Blackman, F. F. Ann. of Bot. 14: Geer 1900. 
Wille, N. Nyt Mag. for Naturvid. 39: I-22. 1901. 
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