LABORATORY STUDIES OF CRYPTOGAMS 159 



lens examine the thickened tips. Have the minute raised spots 

 openings? 



357 (Compound or Simple). With a wet razor nialve 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 (oiigonia), any rela- 

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

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

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

 if any, and adjacent external surface of the tJiaUus (or geneial body 

 of the plant). Sliow a few oogonia in proper proiiortion and form, 

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

 ceptac'e. 



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 tlie antlieriiHa. If necessary 

 pick one of the sections apart with needles — oi' mi'rely squeeze it 

 enough under the cover glass (o break it up — in older to see how 

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

 indicate on the diagram bf foie made the relative size and the posi- 

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

 oogonia are not found togethei', use two diagrams.) 



359 (Simple). Polysiphonia,! one of the Red Alga;. — Draw the 

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

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

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

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

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



360 (Compounil). Are the iilaments of the thallus (or plant 

 body) composed of nrore than single rows of cells? Plow do the 

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

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

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

 from view.) Draw a tetrasporaugium 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 teirasporanyia is to be jirovided. 



