PTERIDOPHYTES 89 
necks bend backward? How would a section 
have to be cut to show the venter and neck 
canal-cells? If prepared mounts are obtain- 
able, study and draw an archegonium and the 
cells adjacent to it. Compare it with the 
moss archegonium in position and structure. 
Fertilization takes place with the egg thus em- 
bedded in the gametophyte tissue. 
B. THE SPOROPHYTE. 
1. Development and general structure——The oospore 
begins its growth without leaving the place where 
it was formed. It soon develops so large a struc- 
ture that it forces its way out, and the leaf and 
root and stem of the so-called fern plant begin to 
appear from the lower surface of the gametophyte. 
Examine young specimens which show the young 
sporophyte not yet free from the gametophyte. 
Sketch, showing the relations between the two. 
Locate specimens which are somewhat older and note 
the condition of the gametophyte. If abundant 
material is at hand observe the stages of growth 
of the sporophyte until it has reached its adult 
size. 
In an old sporophyte note the strong leaf-stem, and 
the leaflets. Sketch, showing part of leaf-stem 
and the leaflet, with its veining. Note the amount 
of chlorophyll-bearing surface which is exposed to 
the light. 
2. Reproduction (asexual)—From the margin of the 
leaflet or from its epidermis there are frequently 
flap - like or shield-like outgrowths that cover 
groups of sporangia. These sporangia produce the 
spores, which are capable of beginning again the 
gametophyte phase of the life history. Sketch this 
