2 Mr. C. B. Plowright. On Mahonia Aquifolia. [Nov. 15, 



31st of May, 1883, Mr. William C. Little, of Stagsholt, March, gave 

 me a freshly gathered specimen of Mahonia aquifolia, upon the berries 

 of which the ^Ecidium was abundant. Knowing that upon the 

 barberry no less than three different iEcidia occur, I determined to 

 prove by direct experimental culture whether this one was the JEcidium 

 herberidis of Persoon (the secidiospore of Puccinia graminis). At 

 10 p.m. on the evening of the 31st May I placed some of the spores 

 upon the cuticle of some wheat-plants which had been cultivated 

 under a bell-glass. In eleven days the uredo of Puccinia graminis 

 made its appearance upon these plants. The details of this, as well as 

 of two other experiments, are appended. On the 13th June I placed 

 some of the aecidiospores upon a piece of wheat cuticle ; in twelve 

 hours they had germinated, and a little later the germ -tubes were 

 seen entering the stomata, in the same manner as those of JEcidium 

 herberidis do (see figure). It is then clear that the ^Ecidium upon 

 Mahonia aquifolia is identical with the JEcidiuM herberidis (Pers.), and 

 is a part of the life-cycle of Puccinia graminis, and is unconnected with 

 the Mcidium magellanicum (Berk.),* and the ^Ecidium of Puccinia 

 herberidis (Mont.).f 



The Mahonia in question is widely cultivated in gardens throughout 

 England and is a favourite evergreen in shrubberies. It is also exten- 

 sively planted in woods as a covert for game. 



Experiment 151.% — Four wheat seedlings, grown in a flower-pot, 

 which have been continuously covered by a bell-glass since the seed 

 was planted (at the end of April), had on 31st May the spores of the 

 Mcidium on the fruit of Mahonia aquifolia applied to their green 

 leaves. The bell-glass was replaced as soon as this was done. On 

 the 10th of June on two leaves pustules of uredo were observed. On 

 the 19th these plants were gathered. Every one of them had the 

 uredo upon it. 



Six precisely similar wheat seedlings, planted at the same time and 

 grown under the same conditions, as control plants, were perfectly 

 free from uredo, and remained so up to the present time (19th June). 



Experiment 152.— Three wheat-plants, grown by " water culture " 

 in a room in the house, were removed from the bottle in which they 

 were growing and planted in a flower-pot on the evening of the 31st of 

 May. To their leaves the spores of the ^Ecidium on Mahonia were 

 also applied as in the former experiment. On the 8th of June the 

 presence of the mycelium of the uredo was indicated by the appear- 

 ance of sickly yellow spots iipon the leaves, and on the 10th the 

 perfect uredo of Puccinia graminis was developed. 



* Hooker, " Flora Antarctica," vol. ii, p. 450, PI. 163, fig. 2. 

 f Montagne Gay, " Elor. ChiL," 7111, p. 46. " Sylloge," p. 314. 

 X The numbers refer to a series of experimental cultures made during the past 

 three years upon the physiology of the Uredines. 



