MESOCARPIN^. 229 



harmony with Archer's description, when he remarks of 

 M. laevis, "the conjugation takes place by short, wide, 

 processes." 



MOUGEOTIA GKLYPTOSPERMA, D.By. 



Diameter of filaments, 10-13 yw ; cells 6-12 times as long 

 as broad. Zygospore large, oval, with a thick, firm, yellow- 

 brown epispore, more or less radiately corrugated when 

 fully matured ; sporiferous cells elongated. 



The position of the zygospore gives the appearance of a 

 Mesocarpus, but the distinction between the two genera 

 must determine its proper place. In Mougeotia the zygo- 

 spore is the result of the complete fusion of the cell contents 

 of the two conjugating cells, whereas in Mesocarpus the 

 spore is the result not of the complete coalescence of the 

 green contents of the two cells, but only of a part thereof; 

 the spore is not a true zygospore, but rather a daughter cell 

 of it. This plant has a true zygospore, hence is properly 

 placed with Mougeotia. 



The only good specimens, from marsh pools, Florida. 



Plate CXLVI, figs. 6, 7, conjugating filaments with spores 

 in different stages of advancement toward maturity ; figs. 

 8, 9, two sterile filaments. 



MOUGEOTIA VERRUCOSUS, "Wolle. 



Diameter of filaments, 13-14 yw ; cells 6-10 times longer 

 than broad, somewhat recurved. Spores transversely oval, 

 shorter diameter 20-25 yw ; and longer axis, 40 /*. Membrane 

 coarsely granular, dark brown. 



Pools, near Mobile, Alabama. A very distinct form. 

 Found only a limited number of specimens ; short fruiting 

 filaments; no sterile cells ; farther observations may modify 

 the above description somewhat. 



Plate CXLVIII, fig. 5, conjugated filaments with matured 

 spores. 



SUBSECTION. MESOC ABPIN^E. 



Green filamentous plants, with chlorophyl more or less 

 axillary. Copulation similar to that of the ZygnemmcB, scalari- 

 form, geniculate or lateral ; the spore formed, however, is not the 

 result of the flowing together of the entire chlorophyl masses of 

 the two cells united ; the chlorophyl does pass out from the two 

 cells and conjoins, but it unites only in part, being separated by 

 two or four partition walls. The spore thus formed is not prop- 

 erly a zygospore, but a hypnospore, or a resting spore. 



