LABOPiATORY STUDIES OF CRYPTOGAMS 159 



lens examine the thickened tijDS. Have the minute raised spots 

 openings? 



357 (Compound or Simple). With a wet razor make a good many 

 sections, as thin as possible, across the tips where the raised spots are 

 thickest, and mount them in water. Have the cavities seen in the 

 sections, and more or less lined with dark bodies (^oogonia), any rela- 

 tion to the little prominences before seen ? Have the cavities (concep- 

 tacles) openings? Make a diagram two or more inches in diameter, 

 showing the cavity of a conceptacle as seen in section, with opening 

 if any, and adjacent external surface of the thallus (or general body 

 of the plant). Show a few oogonia in proper proportion and form, 

 with some of the long filaments that spring from the walls of the con- 

 ceptacle. 



358 (Compound). Examine the oogonia with the compound micro- 

 scope and draw if additional details are found. Look in the same 

 conceptacles (or in others from different plants, according to the 

 teacher's directions) for swollen cells borne on short filaments, much 

 smaller than the oogonia, and distinguished by coarsely granular 

 contents and orange color. These are the antheridia. If necessary 

 pick one of the sections apart with needles — or merely squeeze it 

 enough under the cover glass to break it up — in order to see how 

 these antheridia are borne. Make a drawing to show this. Also 

 indicate on the diagram before made the relative size and the posi- 

 tion of the antheridia in the conceptacle. (But if antheridia and 

 oogonia are not found together, use two diagrams.) 



359 (Simple). Polysiphonia/ one of the Red Algas. — Draw the 

 habit of the plant, enlarged, as seen with the lens. Look for dark 

 round bodies embedded in some of the branches — the tetrasporangia. 

 Do they seem to be somewhat eccentrically placed, or are they situ- 

 ated centrally so as to occupy the whole diameter of the branch where 

 they occur? Draw a portion very much enlarged to show the facts. 



360 (Compound). Are the filaments of the thallus (or plant 

 body) composed of more than single rows of cells? How do the 

 branches end? Into how many separate parts (jelraspores) is the 

 contents of each tetrasporangiuni divided? (It should be said that 

 the tetraspores are so arranged that one of them is always hidden 

 from view\) Draw a tetrasporangium with a short portion of the 

 thallus adjoining. 



361 (Compound). Nemalion, a Red Alga. — Draw a short branch- 

 ing portion to show the filamentous habit. If possible select a piece 

 bearing the small, rounded antheridia at the tips. If so directed by 

 the teacher, seek to identify carpogonia and cystocarps by aid of the 

 figures provided. 



1 Material bearing tetrasporangia is to be provided. 



