1897 | NORTH AMERICAN SPECIES OF AMBLYSTEGIUM 241 
known, is northeastern, extending west to Minnesota, and south 
to Ohio and New Jersey. A. /escurii is Appalachian in its range. 
A. kochit, although represented in herbaria from few stations, 
seems to be widely distributed, being reported from Kansas, 
Minnesota, and the District of Columbia. A. vacillans appears 
to be eastern and northern, probably local; A. munutissimum is 
central and probably local; the other four are northern. One 
striking feature in this distribution is the entire absence of any 
distinctly southern or western forms, though the south has a 
good variety in A. riparium floridanum. It is hardly credible that 
there is such a dearth of Amblystegia in these regions as 
appears. No doubt further exploration in the west and south 
would reveal several forms. 
RELATIONSHIPS. 
The sixteen species here included fall into three groups, the 
type group of twelve species of which A. serpens is the center, 
and two small groups. One of these smaller groups contains a 
single species, A. /escurii; the other is made up of A. riparium 
and its varieties, A. kochit, and A. vacillans. 
EXCLUDED SPECIES. 
Several species accredited to North America have been 
excluded in this paper, because with the available material 
Ihave not been able to separate them from older species here 
Siven. A. fenestratum M. & K. is probably not an Amblystegium. 
It was described froma scrap of sterile gametophyte. A. speirophyl- 
lum M. & K., also sterile, is probably a form of 4. irriguum Or 
varium ; A. distantifolium M. & K. is very near A. irriguum ; A. 
aissitifolium M. & K. and A. subcompactum are, without doubt, 
A. compactum. A. holzingeri R.& C.is Hypnum (Limnobium) clostert 
Austin. 4. schlotthaueri was allowed by me to stand in Barnes 
& Heald’s Key as a subspecies, but on further comparison with 
A. serpens, I have been unable to separate it from that species. 
I have not been able to see A. homalostegium Jaeg. & Sauerb., a 
Plant collected but once, in Alabama; but from the description 
