28 HOW TO KNOW THE MOSSES 



todon, we see that two of the conspicuous character- 

 istics in italics are ''seta greenish-yellow" and ''cap- 

 sule with a long neck." As the seta of the plant we 

 are studying is not yellow and the illustration of the 

 capsule does not look like the capsule of our plant, we 

 pass to the next genus number and turn to the descrip- 

 tion. 2. Ditrichum, we read, has one species with hair- 

 like leaves, and a capsule that is sometimes incHned, 

 but the seta is again yellow and the leaves in the illus- 

 tration are much longer than those on our plant, so we 

 pass to the next description — 4-. Ceratodon. Here the 

 description and illustration correspond perfectly to our 

 specimen. However, to make sure, we glance at the 

 illustrations of the remaining numbers. 6. Dicranella 

 has leaves turned to one side, unHke the leaves of our 

 plant. 7. Oncophorus has leaves crisped when dry, 

 while the leaves of our dry specimen fold straight 

 against the stem. 8. Dicranum has leaves usually 

 turned to one side. The illustration of the capsule of 

 the two remaining genera, 26. Leptohryum and 36. 

 Webera, are so different from the capsule of the moss 

 we are studying that we feel reasonably sure that the 

 plant under consideration is number 4. Ceratodon. 



Although in every instance it is safer to study 

 fruited specimens, about fifty per cent of the common 

 genera can be identified without the aid of the capsule 

 if sufficient care is taken. An illustration to show what 

 can be done with a sterile moss is here given. 



