﻿Halsted : Mycological Notes. 331 



One cannot but wonder what the result might have been had 

 the plants been pressed back into place after the storm or a portion 

 of the plot been shaded or even if the rows had run east and west 

 instead of north and south. 



The Hollyhock Rust. — Mr. J. A. Kelsey, Assistant at the plant 

 hospital, brought me upon March 23d some badly rusted holly- 

 hock leaves from the ornamental grounds of a person living in 

 the suburbs of New Brunswick. The teleutosporic son of this rust 

 {Puccinia malvacearum Mont.) are very prominent and stand up 

 almost like beads from the surface of the leaf. They are more 

 abundant upon the under than the upper side of the leaf, but may 

 arise anywhere even upon the long petioles. 



Upon the leaves examined the sori were in all stages of forma- 

 tion, from the mere yellow orange discoloration of the affected 

 tissue to the fully developed, nearly spherical masses of teleuto- 

 spores. These latter are at first of a light brown color, but the 



point of most interest in this connection was the gray appearance 

 possessed by many of the sori, particularly upon the upper side. 



The first thought upon noticing this wide difference in color, 

 namely that the spores were undergoing germination proved cor- 

 rect, for upon making a microscopic examination the upper cell of 

 each teleutospore in a majority of cases had sent out its promycelium 

 and developed the sporidia. It was the luxuriant growth of these 

 hyphae and spores that had given the peculiar appearance to the 

 sori that under a hand lens looked as if attacked by some delicate 

 mould. 



It would seem that this species of Puccinia produces teleuto- 

 s Pores in very early spring, and that these germinate at once and 

 b y the time the hollyhock is ready to form new leaves there is a 

 large crop of sporidia ready to infect them. 



No signs of any aecidium form is met with in connection with 

 the Hollyhock rust, and the uredo is apparently absent, making 

 thic species one of the Leptopuccinia group. The fungus winter 



>ibernating hyphae in the tissue of the rosette of leaves and 



tart into full vigor at the first suggestion of spring. 



During this season the hollyhock rust has been used 

 demonstrations of promycelium and sporidia instead of 1 



for class 

 the Gyiu- 



V 



