MARCHANTIA POLYMORPHA. 87 



MINUTE STRUCTURE. 



I. VEGETATIVE STRUCTURE. 



Remove the outgrowths from the under surface on different 

 parts of the plant, mount, and observe: 



1. Flat outgrowths; note where and how attached. 1 



2. Two kinds of tubular rhizoids, one with peculiar thick- 

 enings within them. 



3. Draw. 



Make a thin cross-section of the plant body, and observe: 



4. Lower epidermis from which the rhizoids, etc., arise. 



5. A compact mass of almost or entirely achlorous (without 

 chlorophyll) tissue directly above this epidermis. 



6. Special chlorophyllose cells, often in alga-like chains that 

 extend from the compact tissue toward the upper surface. 



7. The upper epidermis, in which sections of the pores will 

 sometimes be seen. 



8. Just beneath the upper epidermis, and extending down to 

 the compact sterile tissue, the columns of pale cells, which 

 are sections of the partitions which divide the upper part 

 of the plant into diamond-shaped air-chambers, in which 

 are the chains of chlorophyllose cells. 



9. Draw. 



II. VEGETATIVE REPRODUCTION. 



i. The cupules and gemmse. Remove and study the form 

 of gemmae. Observe: 



a. The flattened body. 



b. The pair of notches indicating the points of most active 

 growth. 



c. The scar at the point where the gemma separated from 

 the stalk upon which it grew. 



1 These plate-like outgrowths are regarded as primitive leaf-like 

 structures. 



