LABOIiATOnV STUBIliS OF CRYPTOGAMS 161 



how the mold grows. Especially notice the growth on the bottom of 

 the dish where tiie [nugus is spreading away from tlie bread. Make 

 a much enlarged drawing to siiow the groups of stalked sporangia as 

 seen from the side. Are these groups connected in auj' way? Are 

 tliere any special organs for attachment to the sul)stratum? Is the 

 number of sporangia in a group constant? Estimate the heiglit of 

 the sporangial stalks in inches. State the magnification which your 

 drawing represents. 



367 (Compound). AVith a needle carefully remove a bit of the 

 plant, selected from a sfiot where both white (young) and black (old) 

 fruiting heads (xjxiranr/in) can be seen, and mount in water, or better 

 in alcohol followed by a (b.i[i of water. Use first a low power, after- 

 wards a liighiM- power. Have tlu.; threads partitions? Wliat is the 

 color and appearance of tlio contents? C'oinpare an unopened spor- 

 angium with one where the external membrane has given way. 

 AVhat poi'tioji of a wliole head is occupied by spores? Answer by 

 di'awings; show one of the spores separately, niore enlarged. 



368 ( t^nnpouiid). If material is furnished, draw two or three 

 stages to illustrate zygospoi'c formation. 



369 (Compound). Water Molds : Saprolegniacese. — Upon what is 

 the given plant growing? Piemove a bit with foi'ceps and needle to a 

 drop of water on a slide. Examine witli the hand lens, to get an idea 

 of the actual size. Then use low and high powers of the microscope. 

 Are the hypba? o[ even diametei'? Is the protophism dense or thin? 

 What is the sliapc of the ends of the liyplu'e? x\nswer these questions 

 ill di'awing. 



Do you find cei'tain branches filled with denser protoplasm, and 

 somewhat enlarged or clnli-shaped? Can you fiLid stages leading 

 to this condition? Ai-e tlie swollen extreuuties (zoosporan gia) sepa- 

 rated by a partition fiom the rest of the liyphae? Find zoosporangia 

 ill which the protoplasm seems gafliered into many definite masses; 

 others emjitv, with tliese masses (:onxj>orc!<) escaped, but still near 

 by. From what point do the zoospores escape? Draw an unopened 

 zobsporangium, and one ruptured, together with a mass of the spores. 



370 (Compound). Sliort-stalked, globular organs (slightly re- 

 sembling the sporangia of Bread !Mold) will probably be found in 

 abundance in botli old and young stages. Are the youngest ones cut 

 oft bv a wall? 'J'he oldest? A\'hat difference in the contents at the 

 two different stages? You may tlnd gi-adations from one condition to 

 the other. The organs are the noijonin, and when mature contain a 

 number of orw/mres. Ilowmany? Have the oospores walls? If so, 

 are they thicker or thinner than walls (if any) of the zoospores 

 before noted? 



371 (Compound). Look for slender branches with ends applied 

 to the oogonia, and somewhat swollen at the point of contact. In 



OCT. OF IJOT. 11 



