ACHLVA 137 



ter. As the spores swell and become more separated and as the dis- 

 organization continues the curving may continue until a complete circle 

 is formed (fig. 7). If the rupture starts near the tip the spores may 

 spread out like a shaving brush (fig. 10). If the spores are not discharged 

 the disorganization of the wall is not long deferred, but begins in a few 

 hours, just as in Thrauslotheca. In case dictiosporangia arc formed 

 the emptying tubes are often quite long, so long in fact that one often 

 thinks the tubes are going to elongate into threads as in Aplanes, only 

 to find that the spores emerge through them a little later (figs. 4 and 14). 



22. Achlya sp.? Form without oogonia. 



Plate 50 



Weston ('17) found in Massachusetts a speciesof^c^/va which remained 

 sexually sterile during the entire period of culture on different media 

 (over two years). During last August we also found a sterile Achlya 

 (No. I of August 13, 1921) in trash and leaves collected from a branch in 

 Strowd's low-ground pasture, which appears to be the same thing. 

 (Compare also Tiesenhausen's sterile species mentioned on p. 148). 

 We ha\e cultivated this plant continually since (about 7 months, at time 

 of writing) and in many different ways and on many media, but only spor- 

 angia and gemmae have appeared. The latter, while not very peculiar, are 

 often in chains and are of a short, plump type, often spherical, a form that 

 excludes many species with much elongated gemmae. The size and habit 

 of growth of the plant and the form of the sporangia are about that of a 

 typical Achlya, as A. intermedia. On a termite ant the threads grow 

 about 0.5 cm. long and are about 30-70;^ thick below to 20-30[jl thick near 

 the tips. The sporangia are plentiful and proliferate so as to form clusters 

 of several. The gemmae are spherical, ovate or oblong, sometimes in 

 chains of as many as six; their diameter runs up to as much as iio^ for 

 the spherica' ones (figs. 1-4). Results of experiments with chemicals 

 will not be given in detail, but culture media used are gi\-en below to 

 show the reluctance of the plant to form sexual organs: 



12 cc. .05% solution of haemaglobin plus the following salts: 



(i) 2 cc. 2% Ca, (P0,)2 



(2) 2 cc. 2% Ca (XOa): 



(3) 2 cc. 2% K, SO, 



(4) 2 cc. 2% Xa, HPO. 



(5) 2 cc. 2% KH, PO, 



25 cc. of a solution of levulose -^ + leucine goo- '^^'^ solution being replaced by water 

 in 60 hours. Five cultures in nxini temperature 21-26° C. P'ive cultures in ice box temp- 

 erature IO-I2° C. 



