—51— 



upon Dr. Best (who ought to have written this note) suggested that it might 

 be Ditrichum elatum Kindb. And when I submitted the Minnesota 

 plant to Dr. Kindberg, he very kindly looked it over, and recognized it as 

 identical with his species. Subsequently, in an effort to determine the dis- 

 tinctive features of Ditrichum flexicaule dens u in, D. fle.xicaule brevifolium 

 (=D. elation), and D. Macon nii, I received the following materials : 



1. From Dr. Kindberg: Ditrichum elatujn K.\n6herg, collected by J. 

 Macoun at Devil's Lake, Canada, in 1891. 



2. From the Columbia University Herbarium, through the courtesy of 

 Mrs. E. G. Britton: Ditrichum flexicaule densum, from the following 

 stations : 



a. Switzerland, Jaeger, 1866; 



b. Belgium, Gravet, 1875; 



c. " Barwalde," Ruthe; 



d. Schwarzwald, Zickendrath, 1868; 



e. Sweden, Schentz; 



/. Scotland, Fowler, 1S72; 

 <'■. Ditrichum Macounii Kindb., from British Columbia. Macoun, 1890. 



3. From Mr. R. S. Williams: Ditrichum fle.xicaule dens u in (B. & S.) 

 Braith, collected by him in 1898, in the Yukon region. 



3. From the National Hebarium, through the courtesy of Dr. J. N. 

 Rose: Ditrichum flexicaule densum, from — 



a. Norway, Hagen, 1SS7. 



b. Mt. Benson, Vancouver Island, Macoun (Can. Muse. 461). 



c. Ditrichum flexicaule brevifolium Kindb. From Devil's Lake, 



Rocky Mts., Macoun, 1891. 



4. From Mr. Jules Cardot: two plants, both from France, one coll. 

 Cardot, 1883; the other coll. Madiot, 1882. 



5. From Mr. W. E. Nicholson: two English plants; one coll. near 

 Pecca Falls, H. N. Di.Kon, 1886; the other, from Northamptonshire, H. N. 

 Di.xon ("teste Braithwaite"), 1886. 



6. In my own herbarium, I find Ditrichum flexicaule densum, from 

 Germany, Schemmann, 1S95; also from Norway, Dixon & Nicholson, 1900. 



In a considerable series of Ditrichum flexicaule, the species in my 

 herbarium, I find quite a variation, both toward the var. longifolium, and 

 toward the var. densum. It is the latter forms alone that concern us here. 

 Of these I select the following two, 



1. Dr. Bryhn's plant, cfr., from Norway, June, 1900: 



2. Mr. Jensen's plant, from Denmark, September, 1882. 

 These two plants are increasingly smaller than typical forms of the 



species. They also have increasingly smaller leaves. 



Jensen's plant yields little, if anything, in both size and appearance to 

 Canadian Musci 461 ; and Bryhn's plant stands squarely between these and 

 the true species. And, with hardly an exception, the other plants cited 

 aboVe are smaller, in more dense cushions, with variously shortened leaf 

 apex, and young shoots vigorous or slender, according to climatic conditions. 



