ptehidopjitta. 211 



the small fibro-vascular bundle in the midrib. Study the epidermiL. 

 which contains numerous breathing-pores. 



(6) Carefully dissect out from the fruiting cone of a Little Club- 

 moss several spore-cases, the lower ones with four large spores, the 

 upper witli many small spores. Examine in like manner a cone of 

 Lycopodium, in which but one kind of spore will be found. 



(a) Search the borders of lakes, ponds, ditches, and slow streams 

 for Quillworts, which may be at once distinguished from grasses, 

 rushes, etc., by the spore-cases on the bases of the leaves. Although 

 they are rarely collected, they may doubtless be found in almost 

 every locality in the United States. 



(d) Collect pteridophj-tes in fruit and dry them under pressure, 

 afterwards gluing them to sheds of heavy white paper for herbarium 

 specimens. The best size is 43 centimetres (16^ inches) long, by 

 30 centimetres (11| inches); this is the size adopted by the botanists of 

 this country and used in the large herbai-iums. 



(e) For the identification of the species of pteridophytes of this 

 country the student may profitably use "Our Native Ferns and 

 their Allies;" by L. M. Underwood. 



