36 NEW YORK STATE MUSEUM 
herbarium, a set of good and well prepared specimens taken in 
the various stages of development from flowering time till the 
ripening and fall of the fruit, is required. 
The genus Crataegus, as represented by our species, includes 
shrubs and trees which may be roughly but easily separated from 
species of other genera of the same family by the long spines or 
thorns with which their trunks and branches are armed. The 
common and local names applied to these plants are thorn, thorn 
apple, thorn bush, thorn tree, haw and hawthorn. They are nearly 
all suggested by this very prominent character of these plants. 
Some species are small shrubs, only 2 or 3 feet high with a basal 
stem diameter of scarcely 1 inch, others are trees 30 feet or more 
high with a basal diameter of the trunk of 1 foot or more. There 
is no well marked line of distinction between those which are 
classed as trees and those which should be called shrubs. They 
insensibly run together. The same species may be a shrub in one 
place and a tree in another. 
The branches of many species are widely spreading giving a 
broad rounded head to the tree similar to that of an appletree. 
Often the lower branches spread horizontally and the upper 
diverge at a small angle giving a more conic outline to the top. 
The punctate thorn usually has most of its branches horizontally 
spreading. This gives it a broad, flattened or depressed head and 
makes the species easily recognizable at a distance. The shrubby 
species branch from the base and when several clumps grow near 
each other they form almost impenetrable thickets. The young 
shoots of the branches are at first green but with advancing age 
the upper surface gradually assumes a reddish brown or other ° 
color which later encircles the whole shoot. During the second 
or the second and third years the color becomes, in most species, 
some shade of gray or ashy gray. 
The spines that grow from the trunk and branches are modified 
or peculiarly developed branches. They are themselves sometimes 
branched and generally they agree in color with the branch to 
which they are attached. They usually have a bud at one side of 
the base and sometimes one on both sides. These buds develop 
