INTRODUCTORY. 
Essex County offers to the botanist a field attractive and 
interesting in many ways. The open country, deep woods, 
and numerous swamps contain the usual number of species 
found in such localities, while a large river, the Merrimac, 
furnishes a valley in which grow many plants not else- 
where found in the county. There are upwards of fifty 
ponds, from four to four hundred acres in extent, rich in 
water plants and subaquatics. Though there is no con- 
siderable bill or mountainous district, it is sufficiently far 
north to have several representatives of higher latitudes 
and even a few alpine and sub-alpine species in the flora. 
Along the seashore is found an abundance of plants 
peculiar to the region of salt-water marshes and beaches, 
while in the ocean and inlets grow about one hundred and 
fifty species of alge. These last named collecting grounds 
offer an opportunity to study, from fresh specimens, classes 
of plants from which the inland botanist is almost wholly 
debarred. 
The land plants of the county belong decidedly to the 
northern flora although not so arctic in their character as 
the lichens and alge. There is an almost total absence 
of many species common from Cape Cod southward and 
often found just south of Boston. In contrast to this 
the Magnolia glauca is still quite abundant at Glou- 
cester, but not found again north of New Jersey. At 
C11) 
