TYPES OF CRYPTOGAMS; THALLOPHYTES 



251 



FIG. 184. Kockweed (Fucus). 



zoids from same, x 330. 



can be detected. After making the 

 microscopic examination which follows, 

 note what correspondence of structure 

 with color has been observed. Cut very 

 thin sections through fruiting tips from 

 different plants, keeping those from each 

 plant separate. Be sure that some of 

 the cuts pass through the conceptacle as 

 near the middle as possible. 



Examine with a power of about sixty 

 diameters sections from different fronds, 

 searching for one kind containing rather 

 large egg-shaped cells and another con- 

 taining bundles of numerous smaller 



sac-shaped cells. With a power of 200 ^, antheridia borne on branch- 

 diameters Study the details of the sec- ing hairs, X160; S, anthero- 

 tions. Note the character of the cells 

 forming the surface of the frond, those 

 of the inner structure, and those limit- 

 ing the cavity of the conceptacle. In a 

 conceptacle cut through the middle note 

 the form of the orifice. Examine the 

 slender hairs or filaments (paraphyses} 

 which, arising at right angles, line the 

 walls of the conceptacle. 



294. Oogonia and Antheridia. In 

 conceptacles containing egg-shaped cells 

 (oogonia) note the form, 

 mode of attachment (ses- 

 sile or stalked), and dif- 

 ferent stages of develop- 

 ment. At maturity the 

 contents are divided, 

 forming eight oospheres; 

 but not all can be seen FIG. 185. Rockweed (^MCMS). 



at once, some being k e _^>ogonium, its contents dividing into eight oospheres, 

 x 160 ; B, an oosphere, escaped, surrounded by an- 

 neath the others. therozoids, x ieo. 



