36 NEW YORK STATE :MUSEUM 



herbarium, a set of good and well prepared speeiinens 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, haAv 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 Avith 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 flrst 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 ashj gray. 



The spines that grow from the trunk and branches are modified 

 or peculiarly develojjed 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 



