On the salivary Defluxions of Horses. 
Wilmington, December 27th 1810. 
My Dear Suir, 
The plant that has been supposed to produce pétya- 
ism in horses, of which I gave you a verbal account last 
summer, and of which you now wish a description, I 
take to be Euphorbia maculata of Linneus. It is placed 
in the class of dodecandria, and order monogynia, of the 
sexual system. The genus is characterised as follows, 
in the last edition of the system of nature. 
Calyx 1 leafed inflated, inferior: nectaries 4 or 5, 
standing on the calyx : capsule on a pedicle 3 lobed. 
The noxious species which is the particular object 
of our investigation, is thus described in the same work. 
Forked : leaves serrate oblong, hairy ; flowers auxil- 
lary, solitary : branches spreading. 
Leaves when young, marked with a brown spot, 
The Euphorbia are a very numerous as well as natural 
family of plants, and all the species appear to possess a 
particular acrimony. 
Out of one hundred and twenty-two species enume- 
rated in Turton’s edition of Linneus, only five of that num- 
ber are described as natives of North America ; several 
other species, however, are now known to the botanists. 
There are three species to be met with in this neigh- 
bourhood viz. The E. colorata, E. canescens, and E. ma- 
culata. The E. colorata is generally found growing in 
uncultivated situations, but mostly within uncultivated 
enclosures, asin hedges and by the side of fences. It is an 
erect plant, and grows tothe height of several feet; branch- 
