60 



distinguish between aquatic and sub-aquatic; if entirely sub- 

 merged or above water mark. Distinguish between swamp 

 plants or brook-loving forms. Habitat 4 is fields, roadways and 

 waste places. Habitat 5 considers those plants found on stones 

 or rocks. Note carefully whether the plant grows from a slight 

 soil substratum or whether it grow quite close to the rock. 



Fig. 3. Capsule, with calyptra removed. 



3. The calyptra is the next point of classification. Is the 

 calyptra cucullate or mitrate? Often the calyptra is wanting, 

 then we pass on to: 



4. The capsule: This is a very important diagnostic character. 

 Most capsules are either cylindric or ovoid. A few assume odd 

 shapes; as the urn of Pottia; the square of Polytrichum; the sphere 



