262 CARDOT AND THERIOT [3 2 ] 



From St. Matthew Island (Trclease, 2151 in part). 



We found only a. few stems of this moss, mixed with Bctrbzda 

 brachypoda Card. & Ther. and a Bryum. By the pellucid margin 

 of the leaves, it is nearly related to P. obtusifolia C. Mull. (P. 

 heimii arctica Lindb.), but it is easily distinguished from it by its 

 pointed leaves. It also closely resembles Desmatodon systylioides 

 Ren. & Card., from Labrador, which is probably also a Pottia of the 

 same group, but it differs from this species by its ovate, shorter and 

 proportionately wider capsule, its longer and more finely beaked lid, 

 its shorter and more briefly acuminate leaves, and finally by its areola- 

 tion formed of larger and less obscure cells. 



According to J. M. Macoun P. heimii typica has been recorded by Kindberg 

 from St. Matthew Island and from Bering Island. 



Didymodon rubellus Br. eur., fasc. 29-30, p. 3, pi. i. 



From Juneau (Trelease, 2178) ; Port Wells (Trelease, 2272, 2283) ; 

 Agattu Island (U. S. S. Albatross exped., 36) ; St. Matthew Island 

 (Trelease, 2143, specimen in bad condition, and determination doubt- 

 ful) ; Bering Island (J. M. Macoun). 



Didymodon baden-powelli Kindb. Ott. Nat., v, p. 179. Macoun, 



Cat. Can. pi., vi, Musci, p. 262. 



From St. Paul Island (J. M. Macoun). 



Contrary to Kindberg's description, the leaves are entire or nearly 

 so on the specimen we have seen. It is probable that this moss is but 

 a form of D. rubellus. 



Trichostomum cuspidatissimum sp. nov. 



(PI. xiii, fig. 4"-'.) 



Dioicum, elatum, compacte cespitosum, fusco-lutescens. Caulis 

 erectus, circa 5 centim. altus, dense foliosus, rufo-tomentosus, ramis 

 erectis numerosis. Folia siccitate crispata, madore erecto-arcuata, ad 

 apicem caulis et ramorum congesta, fragilia (acumine saepe effracto), e 

 basi ovata sensim et longissime acuminata, 3-3.5 millim. longa, 0.45- 

 0.7 lata, marginibus planis, superne inflexis, papillis prominentibus 

 crenulatis, costa angusta, 80-90 ^ basi lata, in cuspidem acutissimam 

 longe excurrente, cellulis inferioribus rectangulis, 5-6 long, quam lat., 

 lutescentibus, superioribus plerumque quadratis, 10-12 JJL latis, opacis, 

 grosse papillosis. Caetera desunt. 



From Hall Island (Brewer and Coe, 674). 



A fine species, easily distinguished from the large forms of T. muta- 

 bile Bruch, and its var. cuspidatum Limpr. (T. cuspidatum Sch.), 



