While it is very difficult to draw up a diagnosis of the difference 

 between this plant and Tylostoma albicans, the plants are not the same, 

 and our photograph will show it better than our description can. This 

 plant in general appearance very much resembles mammosum, but is 

 uncolored and has almost smooth spores. Albicans belongs to a differ- 

 ent type of plants in shape and cortex from mammosum. 



SPECIMENS IN OUR COLLECTION. 

 Australia, D. McAlpine, J. G. O. Tapper. 



TYLOSTOMA PYGMAEUM (Plate 78). Peridium uncolored, 

 dirty white with a small, tubular, circular, protruding mouth. Cortex 

 adhering, separating imperfectly, particles adhering to the peridium, 

 thickened and persistent at the base. Stem slender, pale, rough, longi- 

 tudinally striate but not scaly. Capillitium hyaline, swollen at the joints. 

 Spores 5 mic., strongly asperate. 



This little species is of a southern range in the United States, and 

 in general appearance could be described as a pygmy Tylostoma albi- 

 cans. It differs from that species in its small size and rougher spores. 



SPECIMENS IN OUR COLLECTION. 



Texas, W. H. Long (three collections). 

 Florida, Theo. L. Mead, Mrs. M. A. Noble. 



Group 5. 



TYLOSTOMA MAMMOSUM (Plate 78). Peridium pale cas- 

 taneous color, u'ith a darker mouth, smooth. (The cortex in the type 

 form usually peels away entirely from the peridium ; sometimes it is 

 partly adherent.) Mouth small, tubular, protruding, always (in the 

 type form) darker than the remainder of the peridium. Stem slender, 

 pale or dark castaneous,f smooth or striate, ver\ slightly if at all scaly. 

 Capillitium subhyaline, with frequent strongly swollen septa. Spores 

 5 mic., granular. 



The typical form of Tylostoma mammosum with its small, smooth 

 head and dark mouth is the most frequent species in Europe.^ hut does 

 not occur in America. 



It is the only species that I know in England, and is frequent in 

 France, Germany, Sweden and northern and central Europe generally. 

 In Italy it appears to be replaced mostly by other species. 



t In some collections notably darker than others. 



} We have received twelve collections. There are twenty-one in the general 

 herbarium, Museum of Paris, thirty-one at Kew, nineteen at the British Museum, 

 {"1, y "9 ne at Berlin, a dozen sheets in Persoon's herbarium, all typically this same 

 ;ie plant, which is quite common and very constant in Europe. 



!J t r,J lf l s beon tne custom in America to call everything with a portruding 

 '"*" 1 y'ostoma mammosum. No plant grows there that corresponds entirely 

 to the European plant. Miss White industriously collects the records and presents 

 showing that Tylostoma mammosum occurs in sixteen different states, 

 is doubtful if she ever saw a specimen from America that could not bo dis- 

 tinguished from the European. A form does occur in America that is close to the 

 European, but it is very rare. The usual form in America is quite different. 



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