UNDERWOOD: REVIEW OF THE GENERA OF FERNS 259 
1788 
" L'Heritier (Sertum Anglicum, 30, 31) established the genus 
Dicksonia based on D. arborescens from St. Helena and D. culcita 
of Madeira. This in later times has been widely extended to in- 
clude plants of the greatest diversity of structure and habit and 
from it certain genera have justly been separated. 
1788 
Swartz (Nova Genera et Species Pl. 128) established the 
genus Marattia based on M. alata of the West Indies. The genus 
is usually credited to Smith, 1793. The above date prevents the 
genus from yielding to Myriotheca Comm. 1789, which is probably 
the same altho it was founded with no type species as a voucher. 
1789 ; 
Jussieu (Genera Plantarum) established the genus Darea men- 
tioning no type, and quoted Myriotheca Comm. also with no type, 
in addition to the twelve original Linnaean genera. In the second 
edition (1791) the same genera are repeated, but in a footnote is 
a question if Caezopteris Berg. is not the same as Myriotheca 
Comm. Later writers have usually referred Darea and N ris 
to Asplenium, possibly without the best of reasons. 
1'790 
Necker (Elementa Botanica, 3 :) added the genera Achomanes 
(313), Gleichenia (314), Psidopodium (315), Onopteris (316), and 
Oetosis (318). None of these are based on types and no earlier 
references are cited. Pfeiffer regards Fsidopodium as the equiva- 
lent of Aspidium, and Onopteris of Asplenium, and Moore holds the 
same opinion regarding the latter. Oetosis and Glechenia, Pfeiffer 
regards as doubtful, but Moore places the latter as a synonym of, 
Aspidium. Achomanes was later taken up by Presl for a sub- 
genus of Hymenophyllaceae but is commonly regarded as a syno- 
nym of Trichomanes. Since these genera are neither represented 
by types nor can be recognized with certainty, it is best to regard 
them for what they are worth—nonentities—in other words to 
disregard thém as mere names with no bearing on the question of 
priority. 
