\ 
268 ESSENTIALS OF BOTANY 
(/) The female receptacles, stalked structures with finger-like re- 
curved arms radiating from the center. With the magnifying glass 
Fic. 192. Section through An- 
theridial Receptacle of Mar- 
examine the under surface of a very 
mature receptacle and note the young 
sporophytes, or spore-plants, hanging 
from the receptacle. Draw. 
344. Minute Structure of Thallus 
and Buds. — Cut thin cross-sections 
of the thallus and examine with Lp. 
and then with m.p. Note: 
(a) The general structure of the 
thallus, with a firm upper epider- 
mis, spongy parenchyma beneath it 
(which serves for the storage of re- 
serve food materials), and a thin 
chantia. (Magnified.)° lower epidermis. 
a, antheridium. 
branching threads, made of pear-shaped cells. 
Compare these cells with others of the thal- 
lus as regards the number of chlorophyll 
bodies which they contain. What effect do 
these cellular threads have on the amount 
of surface for photosynthetic work in the 
air-chamber ? 
(c) The rifizoids. From which surface 
do they spring? Are they all alike? 
Make a drawing to illustrate the general 
structure of the thallus, showing position 
of the air-chamber and attachment of the 
rhizoids. Make a detailed, highly magni- 
fied drawing of the air-chamber. 
Pick out from the cups several buds and 
examine them with m.p. Note: 
(a) The shape of the buds. . 
(0) The notches which show the posi- 
(6) The air-chambers beneath the 
pores, each containing many short 
Fic. 198. Sectional View 
of an Antheridium of 
Marchantia. 
a, antheridium; s, sperms. 
(x 700.) 
tion of the growing points of the bud. How many are there? 
(c) The minute stalk of each bud. How is this attached? 
