—99— 
I am convinced. Gyroweisia Barbula (Schwaegr.) Par. of the West Indies, 
Florida, Bermuda, etc., originally described as a Gymnostomum, has been passed 
hopelessly from genus to genus and its exact affinities are still unknown, further 
than that it is a tropical or subtropical representative of the Pottiaceae in the 
broad sense of Brotherus. G. brevicaulis (Hpe.) Broth, of the East Indies is a 
somewhat parallel phenomenon with peristome-teeth. Fleischer, whose sense 
for moss-relationships is good, has included it in Didymodon,'^^ but the latter as 
it appears in recent bryological works has long ceased to be a natural genus, if 
it indeed ever was one. G. obtusifoha (Hpe.) Broth, from Mexico is a plant in 
many ways suggesting relationship with the Mexican species of the genus Globu- 
lina C. M. But this genus has at present no acceptable status in the moss-system, 
as the Mexican and South American species comprising it are evidently not too 
closely related, nor are either clearly set off from the mass of pottiaceous forms. 
G. barbulacea (C. M.) Broth, from Mexico I have been permitted to see through 
the kindness of the director of the Botanical Garden at Berlin-Dahlem. The 
specimen was a single plant inserted in a split piece of mica and while affording 
a good idea of the peristome and capsule did not permit so clear a demonstration 
of the leaf-characters without the possibility of injury to the specimen. I was 
unable to identify the species with anything else known to me, but do not regard 
it as at all closejy related with any of the other plants included under Gyroweisia. 
On the other hand, mosses placed by Mrs. Britton and Mr. Williams in 
Gyroweisia seem to me to show a far better sense of natural relationship, if the 
genus can be extended beyond the two older species or should exist at all. Mrs. 
Britton's better judgment has, in literature, unfortunately been obscured by a 
new generic name of Cardot, so that her species appears as Dactylhymenium 
Pringlei (E. G. Britton) Cardot. The species is Mexican; besides the original 
station at Chihuahua there is in the herbarium of the New York Botanical 
Garden an earlier specimen collected in 1875 by Dr. J. G. SchafTner in the Valley 
of Mexico, the specimen according to label having come as No. J/ from the 
herbarium of A. Vigener. It may also be claimed for the United States flora on 
the basis of a specimen collected by Rusby in southwestern New Mexico (Grant 
County). Quite similar is the case of Mr. Williams' Gyroweisia boliviana from 
the South American Andes. In describing this species Mr. Williams compared 
it^2 with Hyophila Lindigii Hpe. {Gyroweisia Lindigii Broth.) from the 
Andes of Colombia, which is quite distinct, as Mr. Williams noted, in fact hardly 
congeneric. The relation of the South American and Mexican species to each 
other and of both to the moss generally known as Didymodon tophaceus (Brid.) 
Jur. should be studied further on the basis of the greatest possible amount of 
material. I am persuaded that it is at any rate a close one. The last mentioned 
species is widely distributed in western North America. It is quite out of its 
element in Didymodon, which even without it is all too heterogeneous, and it 
10 Flore de Buitenzorg, V. 1, 333. 1902. 
" Rev. Bryol., XXXVl, 72. 1909- 
12 Bull. N. Y. Bot. Card., 111. ii7f. 1903. 
