378 Natural History Bulletin. 



Iowa and Nicaragua are extremes as far as concerns climate 

 and the Phanerogamic flora, ferns, larger plants generally are 

 totally unlike; yet here are these minute saprophytic organ- 

 isms substantially the same in both latitudes. 



One explanation of the enigma probably lies in the fact that 

 Slime-moulds are essentially plants of the summer season, 

 flourishing in summer months the world around. The plas- 

 modial phase thrives and grows in wet warm weather, but for 

 fruiting a certain modicum of dry weather is necessary. In 

 Iowa the alternations of moisture and drouth occur during the 

 months from March to September inclusive, the later months 

 being dry. Nicaragua differs from this only in that her wet 

 and dry seasons in periods of about six months each fill up the 

 entire year. Winter in our climate comes upon the Slime- 

 moulds in fruit, i. e., in their dry condition when they experi- 

 ence little injury from our excessive cold. Too much wet in 

 any case is not good, and it seems that certain parts of Nica- 

 ragua are for this reason almost destitute of Myxomycetous 

 plants. The species common to both countries show in Iowa 

 better types than in Nicaragua, and the best Nicaraguan 

 specimens are from Ometepe where the dry season is most 

 pronounced in character. From the number of species com- 

 mon to both latitudes we may also infer that Slime-moulds are 

 after all well established organisms, little susceptible of any 

 great variation. They have responded but feebly to changes 

 of environment, and the forms they now wear are old. 



The Nicaragua species of Myxomycetes as collected by 

 Messrs. Shimek and Smith are as follows : 



1. Clathroptychium rugulosum Wallroth. 



Typical. Collected at Ometepe by Mr. Shimek where it 

 was comparatively common. 



2. Cribraria exilis Machride. n. s. Plate X, Figs. 6 and 6a. 



Sporangia gregarious, very small but very long-stalked, 

 nodding, spherical, purple-brown, not at all flattened above, the 



