Grinnellia americana, Harv. 9 



beneath the cystocarps from which they come, while the 

 tetraspores are promiscuously distributed in much less abun- 

 dance over the bottom of the dish. A gelatinous secretion 

 begins to form about both carpospores and tetraspores very 

 soon after they pass into the water, which serves to protect, to 

 hold the spores together, and to fix them to the bottom of the 

 dish or other substratum. The fact that they immediately 

 fall to the bottom of the containing vessel shows that they 

 have a greater specific gravity than the frond, which is 

 probably due to the fact that their chromoplasts and other 

 contents are denser than those of the cells of the parent 

 frond. 



In a few hours after the liberation of the carpospores they 

 are so thoroughly fixed to the substratum by the gelatinous 

 secretion, that it is necessary to subject them to the full force 

 of a strong stream of water in order to loosen them. So 

 far as could be determined by experiment, they become much 

 more firmly attached than the tetraspores, which, in every 

 case, are found to be easily detached from their position 

 before germination. These phenomena lead to the belief 

 that the special function of the asexual spores of Algae is 

 identical with that of the asexual spores of Fungi ; viz. 

 immediate distribution. The carpospores differ so little 

 in colour and shape from the tetraspores, both being lake-red 

 and elliptic-oblong, that they are scarcely distinguishable 

 from one another. They agree closely in size, averaging 

 30 \j. by 50 \)., just preceding liberation. Shortly afterward 

 they become more spherical and enlarge to '3,6 /x by 48 fi. On 

 account of the densely aggregated chromoplasts in the newly- 

 deposited spores, it is extremely difficult to distinguish the 

 nucleus. However, when treated with five per cent, acetic, 

 or one per cent, picric acid for ten minutes, washed thoroughly 

 in distilled water, and then stained with Delafield's haema- 

 toxylin, the nucleus of each spore is readily recognized. 



B3 



