207 
On the ground in California (Bolander), without date or locality. 
Specimens received from the Department of Agriculture in 1889, 
in a set of Bolander’s duplicates, and also to be found in the Les- 
quereux herbarium, as we learn from M. Cardot. 
Differing from P. acuminatum in the shape of the capsule and 
length of the seta, having the slender aspect of Entosthodon erice- . 
torum, but with a lobed calyptra, entire leaves; and no trace of a 
peristome. We have thought it best not to use the original 
Manuscript name which I gave it (spherothecum), as there isa 
European species P. sphericum, which is named in reference to 
the globose capsules and a Mexican species, P. subsphericum, Sch. 
The following key is given to facilitate the determination of 
the species of this genus. Only six, of the eleven here enumer- 
ated, are known to occur within our limits, P. turbinatum, P. acu- 
minatum, P. Drummondii, P. immersum, P. Kellermani and P. 
Hlookeri. Two are Rocky Mountain species, P. pygm@eum and P. 
Coloradense ; two are Pacific Coast species, P. megalocarpum and 
P. Californicum » and P. australe, although here maintained 
aS a species, more specimens may perhaps show that it is only an 
extreme form of P. surbinatuw2, into which it grades through the 
Variety Langloisii. Collectors in our Southern States will do well to 
observe this species carefully and try to get its extreme forms. 
P. Drummondji - may be said to be intermediate between P. 
turbinatum and P. lanceolatum, and probably ranges northward 
through the Mississippi Valley. Spore characters have never been 
carefully recorded heretofore, and these seem to furnish valuable 
assistance in determining the species which resemble each other. 
\ ; 
Key to THE North AMERICAN SPECIES. 
Plants 5-10 mm. high, capsules immersed, bordered by two rows of cells. 
: I. immersum. 
Plants 3-5 mm. high, capsules exserted, bordered by 4~7 rows of cells. © 
Annulus narrow, persistent, leaves serrate, 
Plants 2-3 mm. high, seta short, almost immersed, stems leafy. 
f 2. pygmeum, 
Plants 3-5 mm, high, acaulescent, seta exserted, 1-3 mm. long. 
3. Kellermant. 
Annulus double, persistent or falling, leaves entire, 
Plants mm. high, seta short, immersed, capsule pyriform. : ener 
3-4 shy ort, 2 m ‘ Coloradense. ie 
