- 94 - 
will usually discover some plants in which this character can be seen. 
In plants with incubous leaves the bud is turned downward: when the 
leaves are succubous the terminal bud is turned up. So far as possible the 
key has been based upon the leafy or vegetative portions of the plants, but 
in some few cases the characters connected with the reproductive organs 
and capsules are necessary to accurately determine a plant. In most cases 
the characters used can be determined without mounting, if, however, they 
can not be readily made out the parts should be mounted as for the com- 
pound microscope. If one has access to a compound microscope it will often 
prove a very great help, although not necessary to make out the characters 
mentioned. Mnium and Fissidens are sure to be mistaken for Hepatics by 
the beginner unless the midrib or the leaves is noted. 
Key to the Genera and Species. 
1. Leaves entirely or in large part composed of hair-like divisions (easily 
observed if held up towards a strong light) 2. 
Leaves not as above 3. 
2. Plants grayish green, growing over the ground amid mosses in cool 
bogs, at least twice pinnate and somewhat resembling the Fern Mosses; 
leaves divided to base into hair-like lobes Trichocolea. 
Plants dark green, much smaller, growing chiefly on rotton wood, but also 
found on humus-covered stones and soil ; leaves with a considerable 
solid portion Ptilidium. 
Plants exceedingly minute, looking like a small green alga or moss proton- 
ema. Scarcely recognizable except when fruited; common on decayed 
wood, moist soil, etc Blepharostoma. 
3. Leaves incubous A. 
(Scapania and Chiloscyphus forms may be sought here.) 
Leaves succubous B. 
I 
A. 
1. Leaves complicate-bilobed, upper lobes entire or nearly so (except 
Jubula). See figures and description of Porella 2. 
Leaves sometimes lobed or cleft but not complicate-bilobed .5. 
2. Plants blackish or brownish green, minute, leafy stems 1/25 inch or less 
wide; lobule like an inflated sac (Plate XIV) Frullania. 
Plants often dark olive-green but not often blackish; 1/16 inch in width, 
lobule not sac-like 3. 
3. Under leaves lacking; perianth strongly flattened crosswise (Plate 
XIII) Radula. 
Underleaves conspicuous 4. 
4. Lobule with its longer edge attached to lower margin of lobe (See cuts, 
Plate XIII) Lejeunea. 
Lobule with its shorter margin attached to the lower edge of lobe (Plate 
XIV) Porella. 
5. Leaves mostly entire Kantia. 
Leaves strongly toothed, notched, or cleft at apex 6. 
6. Leafy stems less than 1/25 inch in width Lepidozia. 
