98 THE SAPROLEGNIACE^ OF THE UNITED STATES, 



of successive cultures is very useful here, as in the culture of Bacteria, in eliminating 

 all but a given form. Many species grow well on a flooded slide in the saturated 

 atmosphere of a moist chamber. Cultures may be pretty safely sent by mail in suitable 

 mailing tubes for liquids, but should be sent at the proper stage of development. 

 After some experience in this matter, it appears to the writer that the best time for 

 mailing a specimen which will be more than a day en route is when the sexual organs 

 are just fully formed. They should be placed in a tube filled with clean, preferably 

 sterilized, water and mailed at once. If sent later, the plants are likely to fall in 

 pieces on the way ; while, if sent earlier, the close confinement for some time and the 

 consequent vitiation of the water seem to reduce their vigor so that they subsequently 

 fail to produce sexual organs. 



The application of the above described culture methods to American materials 

 has bhown, as has been said, that these plants are not less abundant with us than in 

 Europe. Among the many samples of material from the most varied sources, which 

 he investigated, only one failed to furnish to DeBary some member of this family. 

 In a large number of cultures from fresh waters of all kinds, rivers, ponds, brooks, 

 spi'ing-holes, drains, and rain-pools of brief duration, in short, from wherever Algss 

 appear, I have failed only two or three times to obtain Saprolegniacece. A single 

 culture may often yield several species. DeBary gives seven as the largest number 

 obtained by him from any one source. I have obtained nine species from two hand- 

 fuls of moss and Algae from a small shallow pool just at the border between a swamp 

 and damp pine woods. On dead branches in this pool grew Mougeotia sp. and 

 Uloihn'cacfce, and over the mosses bordering it crept the filaments of a species of 

 ToJyjJoihrix. Cultures produced at once S. diclina and torulosa, A. Americana, 

 ajnculata, racemosa, var. stelligera, and papillosa, Dictyuchus sp., and L. lacteus. 

 After the material had stood in an open jar near a north window for a few months, 

 the green Algae had disappeared, but the mosses and Tolypothrijc had grown freely. 

 Flies dropped into the jar soon bore Aph. loevis in abundance. 



It is not yet possible to generalize at all concerning the distribution of the 

 species of this family ; but it seems probable that a great majority of them are likely 

 to prove cosmopolitan. One difference has been very conspicuous, however, in the 

 cultures I have studied ; namely, that in those from the ]Srorthern States there has 

 been a distinct predominance of species o[ AchJya, while in those from the Southern 

 States specimens of Saprolegnia, if not different species, have been far more abun- 

 dant. 



The following synopsis of American species can, of course, be only a fragmen- 

 tary representation of our flora, since it covers but few localities and these only in a 



