May £8, 1874. ] 



JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 



427 



Pucoinia, a sharp look-out ought certainly now to be kept on 

 all speoiea coming under Hibiscus, Abutilon, Gossypium, and 

 other genera of Malvaeeto, for Puccinia umbelliferarum grows 

 upon yarious Umbellifera! ; P. lychnideamm is common alike 



in Lychnis, Sagina, Arenaria, &o. ; and P. fallens is found on 

 both Vioia and Trifolium. 



Puccinia malvacearum first appeared in Chili on a species of 

 Althajaj it; next appeared in Australia, where it proved ex- 





pfccjNiA M iLV-icEAnur.1, Mont. 



A. Hollyhock leaf iufected with the disease (natural size). 



B. Pustules burstiuy throufih cuticle, with epidermal hairs, on which some of 



the spores are scattered. Enlarged 40 diameters, 

 c. Section through pustule (or ,*o7hn), showing the clusters of uni-septato 

 spores in situ. Enlarged 40 diameters. 



tremely destructive to the Hollyhock (Althtea rosea, a native of 

 China). Last .Tune it was recorded from France, whilst at the 

 beginning of July it had reached this country, where it imme- 

 diately commenced its ravages on our Hollyhocks with great 

 virulence, and completely killed to the ground all the plants 

 it attacked, both in private gardens and in nurseries. From 

 the south of England it rapidly spread to the north, and 

 during the early spring of this year in certain districts near 

 London nearly every leaf of Malva sylvestris was blackened by 

 this new pest. It has also been recently common in France, 

 attacking the indigenous Malvacerc. 



The Hollyhock disease is remarkable for its extreme viru- 

 lence, for on affected plants a black spot is not merely seen 

 here and there as in common with many species of Puccinia, 

 but the affected plants have every leaf blackened by these 



D. Group of uni-septate spores, seated on tho distinct sterae, or peduncles 



Enlarged »00 diameters. 



E. Hairs from HoUyliocl: leaf, to show proportion between the hairs and the 



fungus. Enlarged .100 diameters. 



All the figures enlarged with the camera Incida. 



obnoxious pustules or sori, which are entirely composed of 

 uni-septate spores seated on stems as seen in section at c, mag- 

 nified forty diameters. Every sorus contains more than ten 

 thousand spores, and in the specimens sent for identification 

 I counted more than a thousand soil on each leaf, therefore 

 each individual leaf was capable of producing [ten million 

 perfect plants of the Puccinia. Figures altogether fail to give 

 any idea of the enormous reproductive powers of this mis- 

 chievous fungus, and as for a cure none is known or likely to 

 be known. The only method of stamping it out appears to 

 rest in at once taking up and burning root and branch of every 

 infected plant. 



The accompanying illustration with description, drawn from 

 Nature with a camera lucida, will serve to give the readers of 

 thia Journal a good idea of the plant as seen under the micro- 



