140 



THE CANADIAN HORTICULTURIST. 



spores (Greek, teleute, the conclusion.) A 



part of one of these dark lines magnified 



twenty-five times is shewn by Fig". 2030. 



The black portion is composed entirely of 



teleutospores, which appear 



only as a black mass, but, 



when magnified 175 times, 



their form becomes more 



distinct as shewn in Fig. '^■iT V^ U 



2031. Two teleutospores, |: 



separated from the mass 



and magnified 300 times, i , 



are represented bv Fig. „ ^^^^ 

 ' - ^ \\o. 2032. 



2032. 



When the ' ' winter is past, the snow melted 

 and g'one, flowers appear on the earth, and 

 the time of the singing of birds is come," 

 then the teleutospores put forth slender fila- 

 ments upon which are formed small bodies 

 called sporidia ; into these the contents, the 

 protoplasm, of the teleutospores is trans- 

 ferred. The sporidia are very easily de- 

 tached, and, borne on the wings of the wind, 

 are carried far from the place of their birth. 

 Such of them as happen in the course of 

 their aerial journey to be dropped upon 

 growing asparagus plants, when the re- 

 quisite temperature and moisture are present, 

 throw out thread-like growths called hyphae 

 which enter into the stalk and there grow, 

 ramifying into a network to which has been 



Fig. 2033. 



given the distinctive appellation mycelium^ 

 This is the veg^etative portion of the fungus, 

 here in the tissues of the asparagus it feeds 

 on the food which the asparagus has elabor- 

 ated for its own use. When the parasites 

 have attained a certain state of maturity the 

 organs of reproduction appear upon the sur- 

 face of their host plant, often the first inti- 

 mation to the cultivator of their presence. 



In the case of this Asparag^us Rust we 

 are informed that in America it usually 

 omits the second stage, known as the 

 aecidial stag^e ; yet it sometimes is seen up- 

 on asparagus growing in uncultivated 

 places, and in beds not cut. It is also 

 known as the cluster-cup form — F^ig^. 2033 

 is a representation of part of a section of the 

 cluster-cup form of this rust magnified 175 

 times showing the rows 

 of decidial spores ; Fig. 

 2034 shows the spores 

 after they have been tak- 

 en from the cup magni- 

 fied 300 times. 



When the cluster-cup 

 stage is present the 

 spores shown in Figs. 

 2033 and 2034 are dis- 

 tributed by the wind, 

 and, becoming deposit- 

 ed on asparagus, penetrate the epidermis, 

 rob the plant in the same manner as the 

 sporidia formed from the teleutospores, and, 

 throwing up the reproductive organs, present 

 to the observer the uredospores, the rust, 

 (ureda, Latin, the blasting of plants). When 

 the aecidial stage is omitted then the fruit, 

 borne by the reproductive organs of the 

 teleutospore sporidia, is the Rust, the uredo- 

 spores. These as shown by Fig. 2035 as 

 they appear to the naked eye, are seemingly 

 mere lines on the surface of the stalk. A 

 part of one of these lines is represented in 

 Fig. 2036 as it appears when magnified 25 

 times, and in Fig. 2037 when magnified 175 

 times. A few of the uredospores magnified 



••• 



Fig. 2034. 



