104 
is daily used in Peru, they might both, .in case of necessity, be: 
substituted for it, in preference:t to all the-other kinds current in 
commerce, because their roots are scarcely distinguishable from 
it, in consistency, colour, smell, or taste, though in a less active. 
degree. 
Among the multitude of cryptogamous. plants which grow in 
the mountains of the Andes, are found many species ef the genus 
Polypodium, which from. their single and very entire leaves; 
more or less lanceolate, are with diticnien distinguishable from 
_ each other without minute examination and comparison. In this: . 
and i in similar cases, it is indispensable that the observer, in order. 
to define well the differences of the species of a genus: bearing. 
great resemblance to each other, should ayail himself of such. 
- comparison, since by defining them separately at different times. 
‘and places, he is liable to. ab almost paifors GeAuitionss 
ee eS 
distinction, take ‘diene for. mere. varieties of the same. species, 
This:‘may be presumed to. have been the case with collectors of 
the different species of the Calaguala, whose roots are now sold. 
his criminatel y i in medicine as roots of the genuine Ca-. 
begncle of witch T have here given a description, explaining the. 
cific ‘difference. _ ‘I am under the necessity of extending it, by 
availing myself of the examination and comparison of the Poly-. 
podium Calag wala, with the other two species nearest allied to it,, 
which during my travels in South America I haye observed to. be. 
mix ats and. sold; as one apscies by traders and dealers... 7 
