THE AMERICAN MIDLAND NATURALIST - 63 
Pentaphyllum argenteum (Linn.). 
Potentilla argeniea Linn., Sp. Pl., 497 (1753). 
St. Joseph Co. (A. Woolman, Barnes), Laporte Co. (Deam), 
Notre Dame (Powers) 2024, Bertrand, (Augustine), 9336. 
The type of the Linnaean aggregate ‘“‘genus’’ Potentilla is 
without question Potentilla Anserina Linn., although Dr. Britton 
says it is Potentilla 1eptans Tinn. The latter is without doubt 
the oldest known potentillaceous plant of the pre-Linnaean genera 
Quinquefolium or Pentaphyllum but Linnaeus by the very fact 
that he rejected these names for his aggregate, intimated that 
in selecting the name therefore he selected also the type of the 
group from which he took the name for his nondescript genus. 
Now the plant which before Linnaeus was known as the Potentilla 
of pre-Linnaeans is Potentilla Anserina Linn. The name was so 
first applied by Brunfels. Now it may be argued that by making 
1753 the beginning of our nomenclature we need not accept 
‘historical’? types of genera. Now P. Ansenina Linn. is not the 
oldest plant of the aggregate genus to which Linnaeus gave the 
name Potentilla as already stated, therefore not what we would 
call the historical type of the ‘“‘group.’”’ We believe, however, 
that when Linnaeus took the name for the group he sufficiently 
intimated zpso facto and apart from historical reasons, that when 
segregations were subsequently to be made the name was to 
be retained for the plant that previously had it. If Dr. Britton 
and the followers of.the theory of residues argue that Potentilla 
veptans Linn. is the type historically and that the historical type 
should always be selected, then why is not Panicum talicum 
selected as type of Panicum or Milium instead of putting it in 
a segregate and applying. the name Panicum to a group of plants 
which the originator of the name never knew? Why is Nymphaea 
alba Linn. the undoubted historical type of the genus Nymphaea 
segregated and the original name given to the other plant or 
plants of the genus? In fact as far as one can see no system what- 
ever is followed in the decision of the manner of determination 
which plants are the Linnaean ‘“‘types.’”’ All this illogical 
practical procedure of segregation of Linnaean genera and type 
selection seems to have as its object the avoidance of confu- 
sion. We wonder if they can possibly think they can hope to 
“avoid confusion’’ by applying methods as above outlined. 
We need not discuss why Linnaeus disregarded the centuries- 
