1 iO Twenty- FIFTH Report on the State Museum. 



(5) 



Synopsis of New York Puccini^. 

 PUCCmiA Pers. 

 Uredo spores subglohose^ hi^and spores uniseptate^ supported on a 

 distinct pedunde. — Hand-book of British Fungi. 



The minute plants included in this genus are known by the 

 common names hrand^ mildew and, in one condition, rust. They 

 grow upon the leaves and stems of living plants, and consist of 

 obscure filaments imbedded in the tissue of the affected part and of 

 dense tufts or clusters of spores which sprin'g from them. In many 

 species a discolored spot, which is also sometimes distorted or swollen 

 in appearance, marks the position of these spore clusters. They are 

 at first covered by the epidermis of the leaf, but as they advance 

 toward maturity they push this up in the form of little swellings or 

 pustules. Soon the pressure becomes so great that the epidermis 

 bursts, revealing the little, compact, cushion-like cluster of upright 

 spores, nestling within its ruptured walls. These spore clusters or 

 sori, as they are sometimes called, vary in size in different species 

 and even in the same species, but they seldom exceed one line in 

 diameter. In some species found on grasses, they frequently become 

 confiuent or greatly elongated in one direction and form long parallel 

 lines between the veinlets of the leaf. In one species they are scat- 

 tered about irregularly, in another, crowded together in orbicular 

 groups or patches, and in a third they are both scattered and clus- 

 tered. Sometimes they occur upon both surfaces of the leaves they 

 inhabit, but most often on the lower surface only, and very rarelj^ on 

 the upper surface alone. 



The color of the spores, as seen in a mass, is some shade of brown 

 or black, and at a little distance the affected stems and leaves appear 

 to be blackened in spots as if scorched by fire, whence probably the 

 application of the term " brand " to these plants. 



A transverse septum or partition at or near the middle of each 

 spore divides it into two parts or cells.. In some species the spore is 

 much constricted at this dividing line, causing it to appear as if a 

 band were closely drawn around it. In each cell a small globule or 

 nucleus is sometimes seen, but this is not a constant mark. The 

 young spores are yjaler in color and often more narrow and pointed 

 than those that are mature. The prevailing forms are elliptical, oblong 

 and clavate. Generally, in those species with elliptical spores, the 

 peduncle is short and liyaline, but in other cases it is various, being 

 short or long, hyaline or colored, according to the species. 



Species of Puccinia may be found almost any time from May to 

 October, but the greater number of species appear in late summer 

 and in autumn. Sometimes they persist through the winter, and old 

 stems and leaves may be found in early spring, infested by the 

 Puccinia of the preceding year. 



