93 



Sept. 1907] Cultures of Uredineae in ipo6 20S 



nois, Wisconsin, Missouri; S. perfoliatum L., Indiana, Iowa, Wisconsin; 

 S. laciniatum L., Illinois, Iowa, Kansas. 



II. Uredinia amphigenous, scattered, roundish or somewhat elon- 

 gated, small, 0.2-0.3 mm. wide, by 0.3-0.5 mm. long, tardily naked, dark 

 cinnamon-brown, ruptured epidermis not conspicuous ; urediniospores 

 broadly ellipsoid or sometimes obovate, 13-19 by 15-23 m, wall golden yel- 

 low, about 1.5 A* thick, sparsely and bluntly echinulate, pores 5 or 6, scat- 

 tered. 



III. Telia amphigenous, scattered, roundish or somewhat elongated, 

 small, 0.2-0.3 mm. wide by 0.2-0.6 mm. long, tardily naked, firm, somewhat 

 pulvinate, blackish brown, ruptured epidermis noticeable; teliospores an- 

 gularly obovate, rounded, truncate or occasionally pointed above, usually 

 narrowed below, 12-19 by 26-35 m, wall chestnut-brown, 1.5-2 n thick, much 

 thicker above, 7-10 /*, smooth;, pedicel light chestnut-brown, one to one 

 and a half times length of spore. 



On Juncus tenuis Willd., Indiana, Iowa, Wisconsin, Michigan, Min- 

 nesota, South Dakota, Missouri, New York, Maine, Massachusetts, West 

 Virginia, Louisiana, Texas; /. dichotomus Ell., Florida. 



It has been issued in the following exsiccati : aecial stage Ellis & 

 Ev. Fungi Columb. 1478 ; Svdow, Ured. 1546 ; telial stage Seym. & 

 Earle, Econ. Fungi 52, 528; Griffiths, W. Am. Fungi 244 (host /. tenuis 

 not /. longistylis) ; Ellis & Ev. Fungi. Columb. 2394. 



The following key will serve to separate the three common 

 species of Uromyces on Juncus, when the urediniospores are 

 present. In the absence of uredinia the urediniospores can usu- 

 ally be found to some extent in telial sori, even those that have 

 withstood the winter, and are collected in the spring following 

 their maturity, and especially so if they are parasitized. 



Urediniospores verrucose, pores 2, equatorial U. Junci (Desm.) Tul. 



Urediniospores echinulate, pores 4, equatorial U. effusus Arth. 



Urediniospores echinulate, pores 5-6, scattered....^. Silphii (Syd.) Arth. 



3. Gymnosporangium Nelsoni Arth. xAt the time this 

 species was published it was stated that Prof. Aven Nelson, the 

 collector of the type material, considered it highly probable that 

 the aecia found on Amelanchier in the vicinity belonged to the 

 species. Teliosporic material on Juniperus scopulorum Sarg., 

 sent by Mr. E. Bethel from Colorado this spring, gave the first 

 opportunity to test the suggestion. Sowings were made May 

 29 on the leaves of Amelanchier canadensis, Sorbus americana, 

 Crataegus Pringlei, Pyrus japonica, and Aronia nigra. On June 

 12 a few pycnia were observed on the Amelanchier and Sorbus, 

 but owing doubtless to indifferent growth of the hosts no aecia 

 were formed. The other hosts remained without infection. This 

 helps in a small way to confirm Professor Nelson's suggestion, 

 but is not conclusive. 



SUMMARY. 



The following is a complete list of successful cultures made 

 during the season of 1906. It is divided into two series : species 

 previously reported by the writer or other investigators, and 

 species now reported for the first time. 



