l66 MOSSES WITH A HAND-LENS 



but a careful search will usually discover some plants in which 

 this character can be seen. In plants with incubous leaves the 

 bud is turned downward; whe« the leaves are succubous the ter- 

 minal 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 mount- 

 ing ; if, however, they can not be readily made out the parts 

 should be mounted as for the compound 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 men- 

 tioned. Mnium and Fissidens are sure to be mistaken for 

 Hepatics by the beginner unless the midrib or the leaves is 

 noted. 



KEY TO THE GEXKRA. 



1. lycaves entirely or in large part composed of hair-like divi- 

 sions (easily observed if held up towards a strong light) 2. 



Leaves not as above 3. 



■£. Plants grayish green, growing over the ground amid mosses 

 in cool bogs, at least twice pinnate and somewhat resem- 

 bling the Fern Mosses; leaves divided to base into hair-like 

 lobes Trichocolea. 



Plants dark green, much smaller, growing chiefly on rotten 

 wood, but also found on humus-covered stones and soil; 

 leaves with a considerable undivided portion Ptilidium. 



Plants exceedingly minute, looking like a small green alga or 

 moss protonema; common on decayed wood, moist soil, 



etc Blepharostoma. 



3. Leaves incubous A. 



(Scapania, Chiloscyphus, and Cephalozia forms may , be sought 

 here.) 



Leaves succubous ' B. 



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. 



^. Plants blackish- or brownish-green, minute, leafy stems ^ 



inch or less wide, lobule like an inflated sac (Fig. 94.) .. ..Pi-tdlania. 

 Plants often dark olive-green, but not often blackish; Vb 



inch in width, lobule not saclike 3. 



3. Under leaves lacking; perianth strongly flattened crosswise 



(Fig 99) Radula. 



Underleaves conspicuous 4. 



4. Lobule with its longer edge attached to lower margin of 



lobe (See Fig, 98); plants small; branches arising below 



a leaf Lejeunea. 



Lobule with its shorter margin attached to the lower edge of ' 

 lobe Fig. 96) , plants large ; bi- tri-pinnate ; branches 

 axillary Porella. 



5. Leaves mostly entire Kantia. 



Leaves strongly toothed, notched, or cleft at apex 6. 



6. Leafy stems less than 5^5 inch in width; leaves deeply cleit.Lepidosia. 

 Leafy stems ^ to ^ inch in width, with downward growing 



stolons (Fig. 107) ; leaves toothed Bassania. 



