-87- 



mm. long. Costa vanishing from ^ to | up. Upper ^ of leaf usually hyaline. 

 Alar cells and most basal cells square (sides 12 to 16 mm.) to short rectangu- 

 lar (i to 2). Median cells irregularly rhomboidal to oblong-linear, up to .040 

 or .050 mm. by .012. Cell walls somewhat thickened, especially above. 

 (Plate 21.) 



This species is distinguished from the preceding by its small size and 

 nerve vanishing far below the apex as well as by the short, square alar cells. 

 Found on bare rock in dry places on the Yukon River, just below Dawson, 

 March 19, 1899, (659). 



Karl Mueller described in Flora, 70: 221. 1887, a Bjyum biillatiivi, which 

 he compares with small P lagiobrynni Zieini. As this comparison well fits 

 my plant I was in some doubt as to the two being distinct, but having lately 

 received a specimen of bullatiun from the Mueller collection, through the 

 kindness of the Berlin authorities, the two plants prove to be perfectly dis- 

 tinct, bullatum being an Anomobryuin {Sc/erodiclyon) as described. 



Polyirichmn hyperboreiim R. Br. Lake Lindeman. This plant has a 

 white hair-point like the preceding, but grows up to 8 cm. high or more, with 

 abundant branches. The hyaline lower cells average somewhat narrower 

 and about twice longer than in pilifernm. They are .008 to .012 mm. wide 

 and up to .160 mm, long (686). 

 Polytrichum mconstans Hagen. 



Stems slender, up to 8 cm. high, rather uniformly leaved above with a 

 felt of dark red radicles below. Leaves somewhat distant, irregularly 

 spreading, up to 6 mm. long, lanceolate with costa scarcely or short excur- 

 rent and margins minutely serrulate. Lamellae up to about 24, the median 

 from 5 to 9 cells high, terminating in i or sometimes 2 cells, transversely ob- 

 long in section, about twice wider than high and not or scarcely depressed. 

 Blade of leaf-bearing lamellae on either side of costa of only two layers of 

 cells thick with cell walls on back of leaf not thickened. Leaf-cells in blade 

 between base of lamellae and margin of leaf mostly from .012 by .016 mm. 

 to .016 by .020 mm. (Plate 22.) 



These specimens have been compared with specimens of iiiconstans 

 Hagen in litt., collected by C. Jensen at Lilleelvedal, Norway, lately re- 

 ceived from Harold Lindberg, fil., and are without doubt the same. The 

 species is peculiar in the broad terminal cell of the lamellae, often doubled, 

 the thin cell walls on back of leaf, very small teeth of margin and short ex- 

 current nerve. 



Collected at Lake Lindeman, in swampy places. May 26, 1898 (690). 



Pterigynandrum filiforme decipiens (Web. & Mohr.) Limpr. Lake 

 Lindeman. On rock. This variety is darker colored and grows in larger, 

 looser tufts than the species with the tips of the stems and branches more 

 curved (697). 



Leskea tectorum (A. Braun) Lindb. Lake Lebarge and Dawson. On 

 rock in rather dry places. Determined by Dr. G. N. Best, This species has 

 smooth, broadly ovate leaves, wnth short-lanceolate point. The leaves are 

 very concave, entire, with margin flat above and recurved below. The leaf- 



