THE BRYOLOGIST 
VOL. XII 
November 1909 
No. 6 
NOTES ON AMBLYSTEGIUM. 
By A. J. Grout. 
The preparation of the treatment of Amblystegium for Part V. of my 
“ Mosses with Hand- Lens and Microscope" has been a much dreaded task 
because of the difficulty of getting any adequate idea of the species from 
any published literature or from any accessible collections. 
The task has proved as difficult as expected and I have seen all too 
numerous specimens that I cannot assign with certainty to any single 
species, though it is evident that each belongs to one or the other of two 
closely related and intergrading species. 
Brotherus’ treatment of the genus in “ Die Naturliche7i Planzenfami- 
iien' } I have found the most satisfactory of any, although following Loeske 
largely .he fails to understand one or two of our American species, notably 
Amblystegium orthoclado7i. 
I have found also that European authorities do not understand all the 
difficult and disputed forms, especially hygrophilu77i,radicale, orthocladon , 
and Kochii. Indeed the types must all be seen by one competent author to 
settle exactly what these species are. I have made my decisions by the best 
light I could obtain and I hereby return thanks to many of my European 
and American correspondents for the help the^ have so freely given in plac- 
ing disputed plants. They have not always agreed but their very disagree- 
ments were helpful in explaining some of the worst puzzles. 
This article is written with the idea that some of the facts discovered, 
and some of the opinions formed, will be helpful if expressed more at 
length than will be possible in the book. 
It has long seemed evident that the minute ecostate species do not 
belong with the others. Brotherus and Loeske still retain them in the 
A?nblystegieae but I believe they belong more properly in the Hyp7ieae. 
The remaining unicostate species can readily be divided into four 
groups, two of which are made genera by Brotherus. 
The first subgenus, Eua7nblystegiwn Broth, is characterized by the 
short broad leaf cells, and costa slender for the genus, ending at the 
middle or somewhat above, percurrent in compactu77i and Holzingeri only. 
This includes serpens (L.) B. & S., Juratzkanu7n Schimp., Kochii B. & S., 
C07npactu77i (C. M.) Aust., and Holzingerii Grout sp. nov. Brotherus includes 
varium with orthocladon as a subspecies but to my mind variu7n, while 
intermediate between this group and the next is. much more closely allied 
with irriguimi than any other species, while orthocladon as I understand it 
is most pronouncedly of the latter type and closer to irrigmwi than to 
varium. He also places here A. radicale (P. B.) Mitt, but according to 
Cardot and Cheney this =Hypnu7n Berge7iense Aust. which is the same as 
The September Bryologist was issued September 1, 1909. 
