92 Schuette Hawthorns of Northeastern Wisconsin. 



influences. Therefore no expert author should venture to base 

 a new species on a single specimen or a single or slight character. 

 The definitive characters should be constant and direct. Our 

 attention is first of all attracted by the external differences in 

 plants. Form, aspect, and habit, therefore, are all important in 

 the discrimination of variations and in the elevation of subspecies 

 to species, at least for popular recognition. Plants like the 

 hawthorns require observation and investigation under different 

 conditions of environment before being subjected to further 

 specific or subspecific differentiation. 



After hunting for years for Crataegus crus-galli I found on 

 the peninsula between Lake Michigan and Green Bay, on Wash 

 ington Island, the next island north of Death Door, Wisconsin, 

 a group of nice trees with shining, thick leaves and rather long 

 thorns. I believed I had at length found the desired species or 

 a variety of it, but later discovering my mistake I called this 

 form C. punctata decipiens, and reached the conclusion that 

 C. crus-galli does not occur in our northwest. This view is 

 supported by a specimen received in exchange from the National 

 Herbarium labelled "Crataegus crus-galli" and collected in 

 Minnesota. Although I have not seen the buds and fruits I 

 regard it as C. tomentosa. The error, due to the meagre and 

 misleading descriptions given in current manuals, is very ex 

 cusable. 



Finally, mention should be made of some interesting obser 

 vations on the effects of the cold and moist atmosphere near 

 Lake Michigan. At the outset the entire vegetation on the 

 peninsula between Green Bay and the lake is delayed 3 or 4 

 weeks as compared with that of the surrounding region. Sec 

 ondly, the atmospheric conditions due to the proximity of the 

 water appear to produce variations and freaks in species, even 

 shrubs seeming to be changed into trees. Near Kewaunee, 

 Wisconsin, on an elevated plain, I met with a cluster of trees, 

 each about- 30 feet high and 10 inches in diameter, with the 

 characters of Acer spicatum, the well known shrub% All but 

 one of these trees have since been exterminated by clearing. Qn 

 the southern grassy slope of this plain is a little grove of Cra 

 taegus trees, 1218 feet high and 35 inches in diameter. I am, 

 however not certain as to their specific identity since I have 

 not seen the buds and flowers. 



