EVANS—THE NORTH AMERICAN SPECIES OF ASTERELLA. 249 
quarter century the genus gradually increased in size, partly through 
the transfer of species from other genera and partly through the 
addition of new species. When the Synopsis Hepaticarum was pub- 
lished in 1847 the number of species recognized had grown to 24. 
Five of these were recorded from Europe only, 4 from Africa, 7 
from Asia, and 2 each from North America, South America, and 
Australasia; the two remaining species were reported from both Eu- 
rope and North America, one of them also from Asia. When 
Stephani published his monograph of the genus in 1899,‘ the num- 
ber of species, in spite of certain reductions to synonymy, had more 
than doubled, 69 being recognized. Three of these are recorded 
from Europe only, 14 from Africa, 15 from Asia, 16 from North 
America, 7 from South America, and 11 from Australasia and the 
Hawaiian Islands; the remaining three species are reported from 
both Europe and North America, one being reported in addition 
from Asia, and one from South America. According to the records 
at hand 28 species, 5 from Africa, 11 from Asia, 3 from North 
America, 3 from South America, and 6 from the Pacific islands, have 
been published since 1899, thus raising the total to 97. The majority 
of these additions were made by Stephani in the sixth volume of his 
Species Hepaticarum (1917). The writer hopes to show, however, 
that several of the species recognized by Stephani should be reduced 
to synonymy, and it is possible that others deserve the same fate. 
Trevisan’s attempt to replace Fimbriaria by Hypenantron was 
based on the existence of an older algal genus Fimbriaria, published 
by Stackhouse in 1809. Since this name was soon repudiated by its 
author and has been ignored by practically all later algologists, Le 
Jolis claims that it has no nomenclatorial standing, and that it ought 
not to stand in the way of maintaining Fimbriaria Nees as a valid 
genus. Fortunately the adoption of Asterel/a makes it unnecessary 
to decide this point. Hypenantron as originally described by Corda ’* 
contained a single species, the Swiss H. ciliatum. Since no descrip- 
tion of this species is given, other than that included in the generic 
diagnosis, its identity would be in doubt if Nees von Esenbeck * had 
not listed it among the synonyms of Fimbriaria fragrans. Follow- 
ing the example of Trevisan, certain European writers recognized 
Hypenantron for a while, but it enjoyed a short-lived vogue and 
has few or no adherents at the present: time. 
Two other synonyms, Rhacotheca Bisch. of 1844* and Octoskepos 
Griffith of 1849,° remain to be considered. Rhacotheca was based on 
1 Bull. Herb. Boiss. 7: 84-110, 198-214. 1899. 
* Opiz, Beitr. Naturg. 648. 1828. 
*Naturg. Eur. Leberm. 4: 268. 1838. 
“Seubert, Fl. Azor. 12. pl. 14. 1844. 
® Not. Pl. Asiat. 2: 343; Icon. Pl, Asiat. 2: pl. 69D, f. 1 1849. 
