38 MISSOURI BOTANICAL GARDEN. 



The great Tomentosae Group, with only thirteen species, 

 is certainly not as well represented in Missouri as jt is in 

 many parts of the country east of the Mississippi River, 

 especially in Ontario, where the species of this group form 

 a considerable part of the Crataegus vegetation. It seems 

 remarkable that only three species of the thick-leaved sec- 

 tion of this group have been found in Missouri, although 

 species of thick-leaved Tomentosae are common in northern 

 Illinois. The type of this group, Crataegus iomentosa 

 Linnaeus, is one of the four species of wide distribution 



been found in Missouri 



Group 



and most 



eastern states, has been found in Missouri where there are 

 no indications of the existence of the small but interesting 

 eastern Anomalae Group or of the Bracteatae, Pulcherrimae, 

 Triflorae, Aestivales or Brachycarpae, small southern groups. 

 Although I have made a number of visits to Missouri in 

 the last eight years to study Crataegus and to introduce the 

 most interesting of these plants into the Arnold Arboretum, 

 the real work of collecting and field observation in the 

 genus has been chiefly done in Missouri by Mr. B. F. Bush 

 of Courtney, Jackson County, who has made many jour- 

 neys in the southern counties to collect Crataegus, by Mr. 

 E.J. Palmer of Webb City, Jasper County, which is one of 

 the richest known Crataegus regions in the state, and by Mr. 

 J. H. Kellogg of the Missouri Botanical Garden, who has 

 worked assiduously during several years to increase the 

 knowledge of these plants in the neighborhood of St. Louis. 

 Unaided by their zeal, patience and industry, it would have 

 been impossible for me to have prepared this preliminary 



report. . . r^ wt 



An earlier student of Crataegus in Missouri is Mr. G. W. 



Letterman of AUenton, St. Louis County, who began to 

 study the genus before 1880. In that year he sent seeds of 

 Crataegus to the Arboretum ; and from these seeds were 

 raised the plants which have since been described as Cratae- 

 gus nitida, Crataegus fecu7ida, Crataegus coccinioides, Cra- 

 taegus Dawsoniana and Crataegus succincta; and it was the 



