FUN ARIA HYGROMETRICA. 101 



MINUTE STRUCTURE. 



I. VEGETATIVE STRUCTURE. 



Mount and examine under low or high power, as may be 

 needed to demonstrate the structures and observe: 



1. The rhizoids; their structure and how they arise from the 

 basal end of the stem. Draw. 



2. The leaves. 



a. Thickness in various parts. 



b. Specially differentiated cells along middle of leaf. 



c. Prominent chloroplastids within cells. 



d. Draw, showing in detail the different kinds of cells that 

 compose the leaf. 



3. The stem. 



a. How stem and base of leaf are united. 



b. Whether stem bears chlorophyll. 



4. The protonema. Examine some of the earth in which the 

 moss plants grew, or some of that in which mature moss 

 spores have been sown some weeks previously. If the 

 material is good, it should show: 



a. The alga-like structure of the protonema; cells with 

 chloroplastids; method of branching. Draw. 



b. Buds arising from protonema and gradually developing 

 into the leafy shoots. Draw stages illustrating this 

 development. 



II. SEXUAL REPRODUCTION. 



i. Antheridium. From one of the male plants carefully re- 

 move the leaves, allowing at least a part of the antheridia 

 to remain on the stem. Observe: 



a. The position and general arrangement of the club- 

 shaped antheridia, and 



b. The paraphyses which stand among them and extend 

 above them. 



