THE FERN. 



PTEBIS AQUTLINA. 



THE common brake is widely distributed, growing in 

 nearly all damp, shady places. If the structure of the 

 entire plant is to be studied, they should be collected and 

 used fresh or else preserved in formalin. Early summer 

 is the best time for the collection, though the plants will be 

 in fairly good condition in the early fall. For the histological 

 study the rhizome must be sectioned in the usual way. 

 The sections may be stained, but some of the tissues will 

 show well without stain. 



This organism is composed of organs which are partly 

 underground and partly above ground, the former com- 

 posed of the underground stem, or rhizome, and roots which 

 serve to absorb water and salts from the soil. From the 

 rhizome leaves, or fronds, extend into the air as the chlorophyll 

 bearing parts, with supporting and nutritive organs. 



The leaf consists of a main stem or stalk divided into 

 leaflets, or pinnae and pinnules. It is in the leaf that the 

 food is elaborated from simple compounds and elements 

 .through the activity of the chlorophyll bodies, or chloro- 

 plasts, which are but modified masses of protoplasm. Here 

 are also found organs of reproduction. 



The main object in the study here outlined is an insight 

 into the fundamental structure of a plant, its parts, their 

 relations and functions. A further aim is, by rough com- 

 parison, to discover any similarities of structure and organi- 



