9 BASIDIOMYCETES 



6. Sori in limited areas occasionally anastomosing on the leaves. 



PUCCINIASTRUM. 



Sori forming expanded areas mostly on stems. CALYPTOSPORA. 



The genera of this family are mostly composed of few species. 

 Chrysomyxa is mainly confined to the Ericaceae ; C. pirolae 

 is common on species of Pyrola. Species of Cronartium are 

 found on Comandra, Ribes and Quercus, Species of Coleo- 

 sporiuiii are abundant on various Compositae and are occasional 

 on the common bell wort {Campanula}. The aecidial forms of the 

 last three genera are members of the form-genus Peridermium , 

 which are formed on various conifers. Several of these inhabit 

 the leaves of pines* and one or more species form larger or 

 smaller swellings on the branches or even the trunks of pine trees ; 

 we have seen these on pines in Alabama fifteen inches in diam- 

 eter. Other species of Peridermium are found on species of Abies. 



The species of Melampsora are parasitic on willow, poplar and 

 birch, as well as on various herbaceous dicotyledonous genera as 

 Linitm, Euphorbia and Croton. The uredo forms are best known 

 but are insufficient for distinguishing the species. The willow- 

 inhabiting species of this country especially need careful study. 



Pucciniastrum is best known in this country from the common 

 species parasitic on Agrimonia whose uredo form is everywhere 

 common ; other species are found on Prunus and certain Erica- 

 ceae. Calyptospora has a single species parasitic on species of 

 Vacciniuin causing enlargment of the stems ; Uredinopsis has a 

 few species parasitic on ferns. 



Family 2. Pucciniaceae. 



This family contains by far the largest number of the rusts, in- 

 cluding those that represent parasitic diseases of cultivated plants. 

 Besides the grain-rust belonging to the genus Puccinia with 

 several species, we have other species parasitic on Asparagus, 

 hollyhocks, corn, sunflower, plum and peach, besides numerous 

 species on weeds and various wild plants of nearly every family. 

 Species of Uromyces are parasitic on clover, on beans, on carna- 

 tions, and on beets, besides numerous species on weeds and vari- 



* Cf. Underwood & Earle. Notes on the pine-inhabiting Species of 

 Peridermium. Bull. Torrey Bot. Club, 23 : 400-405. 1896. 



