158 LABORATORY STUDIES OF CRYPTOGAMS 



Place a small drop of dilute (30 per cent) eosin glycerine at the edge 

 of the cover glass so that it \Yill run under. If the glycerine reaches 

 the Spirogyra, many of the cells will now be found with their contents 

 much distorted. Does it appear that the contents are separable from 

 the walls on all sides? Select a cell slightly affected. Is there a 

 definite layer of substance in which the chroniatophores are imbedded? 

 The nucleus, stained by the eosin, will now be readily ma(^e out. 

 Draw a cell highly magnified, showing a part of one chromatophore, 

 the nucleus, and the layer of living substance (protoplasm) where 

 separated from the wall. 



351 (Compound). If material is provided, make drawings of con- 

 jugating cells, showing stages in the process. Label the rounded 

 bodies found w'here conjugation has been effected zygospores. 



352 (Compound). Vaucheria. — Use the hand lens to gain an idea 

 of size and general habit. If the feltlike mass is growing on earth, 

 pick off a little with needles, using care to get rid of soil in the 

 preparation. Mount in water under the compound microscope. Are 

 the filaments septate (partitioned), or not? Focus on the upper sur- 

 face. AVhat is the shape and size of the chromatophores here ? 

 Focus down until the side w^alls stand out sharply. Do the chromato- 

 phores occur only near the walls, or are they scattered throughout the 

 interior of the tubes? Do the filaments branch? 



353 (Compound). Do you find lateral club-shaped (not globular) 

 branches, or somewhat swollen tips of filaments, of a very dark green 

 color (sporangia) ? Are they cut off by partitions (septa) ? 



354 (Compound). Look for short, nearly globular branches, in 

 company with others more slender, lighter green, and somewhat coiled. 

 If any of these can be made out clearly in all parts, draw them 

 (oogonia and antheridia). If the form and attachment are not clear, 

 turn to the figure given by the teacher, and with its help decide 

 whether the oogonia and antheridia are found on the material you 

 have. The species studied and that represented in the figure may 

 not be the same, in which case exact similarity of organs will not be 

 expected. 



355 (Compound). Ectocarpus, exemplifying the Brown Algae. — 

 View with the hand lens, then with higher magnifications. Are the 

 main trunks more than one cell in thickness? The branches? Draw 

 a small, branching portion. Are there any very short branches dis- 

 tinguished by greater thickness? If so, are they more than one cell 

 in thickness, or does each branch consist chiefly of one large terminal 

 cell, or sac, with granular contents? Draw both sorts of branches, if 

 found, labeling the many-celled ones gametangia, and the saclike ones 

 sporangia. 



356 (Simple). Rockweed. — Make a life-size drawing from a 

 branching portion, to show the habit of the plant. With the hand 



