202 PITTONIA, 
which we have at the outset somewhat evasively, but accord- 
ing to old English usage, denominated the Hop Trefoils. 
The various difficulties which systematists have encount- 
ered in attempting to classify these plants arrange them- 
selves naturally and conveniently under three headings: 
first, the generic status of the group; secondly, the natural 
limits of the species; and thirdly, the identification of each 
of the four species named by Linneeus. 
As for their generic status, the author named had them in 
Trifolium, a consideration of no great weight, if we but bear 
in mind that the series of genera jumbled together by him 
under that name begins with Melilotus and ends with Stylo- 
santhes. The better systematists of a generation or two be- 
fore him had expressed some diversity of opinion as to where 
these small trifoliolate papilionace: ought to be placed as a 
natural group; some authors ranging them under Trifolium, 
some under Melilotus, some under Lotus, some under Medi- 
cago, while certainly not less than two original and influ- 
ential authors had named them as constituting a separate 
and distinct genus. Rivinusin 1691 placed them in generic 
rank under the name Lupulinum, and Micheli in 1729 in- 
cluded them in his proposed new genus Trifoliastrum. And 
since Linneus’ time there have been made a number of open 
protests, and by most able botanists, against the treating of 
the Hop Trefoils as congeneric with such plants as Trifolium 
pratense and its allies. Systematists of no less renown than 
Lamarck (1778) and Desfontaines (1798) referred the plants 
to Melilotus rather than Trifolium. Desvaux in 1827 ex- 
pressed the opinion that they ought to constitute a genus, 
assigning the name Curysaspis. Three years later C. B. 
Presl, perhaps unaware of Desvaux's work, designated them 
as a genus which he called Amarenus. 
From true Trifolium, that natural group of which the Red 
or Meadow Clover is typical, these plants differ very strik- 
ingly. No person with mind unwarped by the pedantries 
of the school-master botany of the last century would say 
