Analytic Keys to the Species of Mosses. 
7 $ 
Leaf-cells abruptly enlarged at base , indistinct, linear-vermicular. 
Costa percurrent. H. populeum, 57- 
Costa vanishing. 
Seta purplish, rough throughout. 
Capsule suberect, stem-leaves gradually acuminate H. ceespitosuin, 59. 
Capsule abruptly horizontal, leaves abruptly short 
acuminate with points recurved . . H. illecebrum, 61. 
Seta reddish and rough above, yellowish and smooth 
below.H. Californicnm, 60. 
* * Lid (more or less long) rostrate. 
Leaves obtuse . H. obtusifolium, 169. 
Leaves acute or acuminate. 
-?-*• Cilia solitary or geminate at base. 
Pericheetial leaves erect, serrulate . . . . H. curvisetmn, 91. 
Perichaetial leaves recurved, entire . . . . H. lentum, 69. 
-n- Cilia 2—3. 
Leaves with filiform points. 
Stems short, with erect fasciculate branches, stoloni- 
ferous.H. Yauclieri, 73 a. 
Stems long, prostrate, irregularly branched, not radicu- 
lose .H. piliferum, 74- 
Leaf-points not filiform. 
Leaves serrulate all around. 
Decurrent, excavate at basal angles. 
Perichaetial leaves spreading H. Stokesii, 78. 
Perichaetial leaves reflexed H. Oreganum, 79. 
Not decurrent nor excavate. 
Leaves ovate-lanceolate, acuminate, segments 
split . ..H. Sullivantii, 76. 
Leaves broad-ovate, acute, segments perforate H. pradongum, 75- 
Leaves entire at base. 
Lid not half as long as capsuie H. colpophylluin, 73- 
Lid nearly as long as capsule.H. Ilians, 77 
b. Seta smooth. 
[Homalothecium pseudo-sericeum may be sought here.] 
i. Lid (more or less long) rostrate. 
Leaves apparently 2-ranked; plants of dry woods . H. serrulatum, 89- 
