SELAGINELLA SP. 123 



LABORATORY WORK. 

 GROSS STRUCTURE. 



I. THE VEGETATIVE BODY. 



With a good branch as a specimen, observe: 



1. The position in which the stem grew. 



2. Position of leaves. 



3. The number of rows of leaves, their relative size, and their 

 distribution on the stem. Note how the size and position 

 of leaves are adapted so that all may have sufficient ex- 

 posure to light. 



4. Aerial roots, coming from the stem as branches and 

 descending to the soil. Draw. 



II. THE REPRODUCTIVE BODY. 



At the tips of some branches the sporophylls form a close 

 cluster, known also as a spike or a strobilus. Observe: 



1. The number of rows of sporophylls. 



2. The arrangement of the sporophylls. 



3. Through some of the sporophylls, the sporangia, appear- 

 ing as yellow or red dots. 



4. Draw. 



MINUTE STRUCTURE. 



I. THE LEAF. 



Mount an entire leaf, and observe: 



1. General form of cells in the midrib, the margin, and the 

 body. Examine these in detail, particularly the cells of 

 the main part of the leaf and the peculiar plastids they 

 enclose. 



2. Draw. 



II. THE STEM. 



By means of a cross-section of the stem observe: 



