2 PRACTICAL BOTANY. 



and protect the antheridia ; other specimens again 

 may bear at their apex 



5. The mature sporogonium or spore-capsule, of 

 which the head or theca is supported on a long stalk, 

 or seta. Note in specimens which are not too ripe 



a. The calyptra, a dry fibrous hood, covering 

 the apex of the sporogonium : beneath this is 



I. The lid-like operculum with its terminal beak : 

 this lid may be easily detached, disclosing 



c. The thin membranous, and transitory epiphragm. 



d. The peristome, a fringe of fine fibres, which by 

 their hygroscopic movements assist in scattering the 

 spores. 



e. At the base of the theca observe a swelling called 

 the apophysis. 



/. By carefully removing the leaves from the apex of 

 a plant bearing a sporogonium, it may be seen that the 

 base of the seta is enveloped by a closely fitting 

 sheath, the veil or vaginula, the origin of which will 

 be explained later (page 9). 



Observation of the external characters of a simpler Moss, e.g. 

 Funaria hygrometrica, will give in the main similar results to 

 those above described for the larger Polytrichum. 



B. MICROSCOPIC INVESTIGATION. 

 Oophore Generation. 



II. Cut transverse sections of a mature stem of 

 Polytrichum : mount some in glycerine, others in 

 Schulze's solution or in iodine solution : examine them 

 first under a low power, and observe in those mounted 

 in glycerine 



