THE BRYOLOGIST 
Vol. XI 
July 1908 
No. 4 
THE GENUS ZYGODON IN NORTH AMERICA. 
Elizabeth G. Britton. 
Three species of Zygodon have been listed for the United States and 
Canada but the genus is omitted from Lesquereux and James’ Manual, only 
Z. Sullivantii C. M. being included under Amphoridium. Macoun’s 
Catalogue ( 1892 ) listed Z. viridissimus from sterile specimens collected by 
Drummond at Hudson’s Bay. The same year ( 1892 ) Dr. Small and I dis- 
covered fruiting specimens of a species of Zygodon on the summit of White 
Top, Virginia, which were also published as Z. viridissimus^ , but on com- 
parison with Drummond’s these specimens proved to be so different that I 
concluded they must be a different species and sent them to M. Cardot as Z. 
conoideus by which name they are listed 2 " from Virginia. I also sent them 
to Dr. Braithwaite as Z. conoideus and he generously supplied me with fine 
fruiting specimens of this species from Mucross, Killarney. These were 
compared with ours from Virginia and found to be quite distinct having a 
well-developed peristome. Unfortunately our specimens had capsules that 
were either too old or still immature, and it was not till a subsequent visit to 
White Top that Dr. Small collected abundant material in good condition. 
This proved that our species had no peristome so I concluded it was a new 
species and sent it to M. Genl. de Paris as Z, rufo-tomentosus ined. and it is 
so listed in his index in both editions. Nothing further has been published 
until recently in The Bryologist for March ( 1908 ) Dr. Grout has listed Z. 
conoideus , Z. excelsus and Z. gracilis , from the mountains of North Caro- 
lina with “determinations doubtful.’’ 
We are in much better condition to study our North American species 
now, since Limpricht’s masterly descriptions 3 and Correns’ 4 studies on repro- 
duction of sterile mosses by brood-bodies as well as Brotherus’ 5 synopsis 
have appeared. Dixon’s 6 remarks will also be found helpful. According to 
Brotherus, America is the richest in the number of species, leading with 57 
of which 53 are endemic. He recognizes Z. viridissimus , Z. Sullivantii 
and Z. conoideus for the United States and maintains Z. rupestris Lindb. 
as a distinct species, but does not credit it to North America. It is clear to 
me from recent studies that two of our North American species belong in 
the first section with those having no peristome and that Drummond’s speci- 
1 Mem. Torrey Club 4: 180. PI. 80. 1893. 
2 Musci Am. Sept. 26: 1893. 
3 Die Laubmoose 2: 10. 1895. 
4 Unt. Vermerh. der Laubm. 114. 1899. 
5 Nat. Pflanzenfam. fasc. 215. 460. 1902. 
6 Handbook 236. 1896. 
The May BRYOLOGIST was issued May 1, 1908. 
