92 THE PLANT WORLD 



cup fungus, may be a particularly valuable auxiliary in checking tlie 

 later and more destructive forms. 



Thus far this parasite has been met with only upon asparagus 

 plants that grow wild and produce the cluster-cups in early spring. 

 Spraying in the field may not therefore interfere with the good work of 

 this fungus. It remains to be determined how much this parasite and 

 the Darluca may be depended upon to hold the rust in check, and it is 

 encouraging to have these friends of the asparagus grower come to his 

 rescue so early in the history of the asparagus rust in this country. 



This is not the place, perhaps, to consider the subject of remedies 

 at any length, although it is of vital importance to the growers of aspar- 

 agus. So soon as the " brush " has lost its green it is no longer of use, 

 and the cutting and burning of it in autumn wall secure the destruction 

 of vast multitudes of spores. The plants, consisting as they do of nu- 

 merous fine and very smooth rapidly growing branches, are not well 

 adapted for holding fungicides. Also, experiments show that the ten- 

 der, slender tip may be injured by the ordinary Bordeaux mixture. 

 Perhaps the most successful treatment of the disease is that recentlj^ 

 described by Mr. Sirrine,* who finds that the ravages of the rust can be 

 stayed to a considerable degree b}^ using a resin-Bordeaux mixture, 

 which is applied by means of a horse-power sprayer. 



Mr. J. A. Kelsey, field assistant of the New Jersey College Experi- 

 ment Station, has sliowTi close attention to details in making the draw- 

 ings for the accompanying engravings. 



Description of Figures. 



Pig. I. [a.) An asparagus stem showing uredo form of the rust, natural size. 

 (b.) An asparagus stem showing teleutospore form of the rust, natural size, {c.) A 

 portion of a section of an aecidium cup showing the rows of spores and the mycelium 

 of the fungus and cells of the asparagus stem, magnified 175 times, [d.) Aecidial 

 spores, magnified 300 times. 



Fig. 2. [e.) Portion of uredo sorus, magnified 25 times. {/.) Portion of a sec- 

 tion of a uredo sorus, magnified 175 times, {g.) Uredo spores, magnified 300 times. 

 {h.) Portion of teleutospore sorus, magnified 25 times. (/. ) Portion of a section of 

 teleutospore sorus, magnified 175 times. (/. ) Two teleutospores, magnified 300 times. 



Fig. 3. {a.) A uredo sorus infested by the L>ar/icra, magnified 25 times, (d.) A 

 section of uredo sorus infested by the I?ar/uca, magnified 70 times, {c.) Spores of 

 the Darluca, three of them germinated, magnified 590 times. 



Fig. 4. {d.) A cluster of aecidium cups infested by the Tiiberai/ina — the cups 

 are in the center and the Tuberculina marginal near the spermagonia — magnified 15 

 times. ((?. ) Portion of a section of the 7"«(5^;r«/z;/a, magnified 175 times, {/.) Spores 

 of the Tuberculina, magnified 590 times. 



New Brunswick, N. J. 



Bull. N. Y. Agric. Exper. Station, No. 188, December, 1900. 



