90 



BA SID 10 M YCE TES 



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. 

 ChrysoDiyxa is mainly confined to the Ericaceae ; C. pirolae 

 is common on species of Pyrola. Species of Cronartium are 

 found on Couiaiidra, Ribcs and Quercus. Species of Coleo- 

 sporiiun are abundant on various Compositae and are occasional 

 on the common bellwort (^Campaimld). The aecidial forms of the 

 last three genera are members of the form- genus Periderrnm??!, 

 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 Melauipsora are parasitic on willow, poplar and 

 birch, as well as on various herbaceous dicotyledonous genera as 

 Linum, 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. 



Pucciniastruvi is best known in this country from the common 

 species parasitic on Agri)no7iia whose uredo form is everywhere 

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

 ceae. Calyptospora has a single species parasitic on species of 

 Vacciniwn causing enlargment of the stems ; Uredinopsis has a 

 few species parasitic on ferns. 



Family 2. Pucciniaceae. 



This familv contains bv far the largest number of the rusts, in- 

 eluding those that represent parasitic diseases of cultivated plants. 

 Besides the grain-rust belonging to the genus Puccmia 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. 



