﻿58 Arthur and Fromme: A new Endophyllum 



The type of Aecidium tuberculatum was collected by Mr. E. 

 Bartholomew on leaves of Callirhoe involucrata, Rooks County, 

 Kansas, September 15, 1887. It has since been found on this 

 host at several stations on the prairies of eastern, central and 

 western Kansas and southern Nebraska. The Sidalcea rust is 

 known from several points in the mountains of central Colorado 

 and from a single collection in south central Wyoming (Text 

 FIG. 2). 



The infection of the various hosts through the sowing of 

 basidiospores has not so far been demonstrated but experiments 

 are under way the results of which should be apparent next spring. 



Pycnia are apparently obsolete in this species ; a careful search 

 of infected leaves and a study of microtome sections brought forth 

 no traces of them. 



The teliospores are normally one-celled, but occasional two- 

 celled spores are produced and one or more of them may be found 

 in any mount (FiG. 2). Their wall thickness, coloring and 

 verrucose sculpturing is like that of the one-celled spores, from 

 which they differ only in form and the presence of a horizontal 

 median septum. They are found in microtome sections of the 

 sori scattered among the one-celled spores in the upper part of 

 the spore chains. Each cell contains two nuclei the products 

 of the conjugate division of the two nuclei of the one-celled spores 

 from which they arise by a vegetative development. 



These two-celled teliospores oi Aecidium tuberculatum are sug- 

 gestive of those found normally in the genus Pucciniosira, which 

 has catenulate, uniseptate teliospores accompanied by a peridium 

 and borne in a cupulate telium that is to all external appearances a 

 true, but diminutive, aecidium. The other morphological features 

 of the sorus and spores of Aec. tuberculatum, especially the large, 

 bullate sorus, the fragile, slightly differentiated peridium, and the 

 breaking apart of the spore chains in older sori giving the impres- 

 sion that the spores are compacted without order are, however, 

 characteristic of the genus Endophyllum to which it is, therefore, 



Endophyllum tuberculatum (Ellis & Kellerm.) comb. 

 Aecidium tuberculatum Ellis & Kellerm. Jour. Myc. 4: 26 

 O. Pycnia unknown, probably not formed. 



