PENICILLIUM 463 



decretus (Massee), was sent to Kew from Singapore by 

 Dr. Ridley, who described it as being destructive to coffee-trees, 

 beginning at the tips of shoots and extending backwards, a 

 very unusual mode of parasitism. It bursts through the 

 epidermis as minute, rounded, white pustules, which soon 

 increase somewhat in size, and change to an orange-red colour 

 and a gelatinous consistency. 



Spore-beds more or less circular, slightly convex, white, 

 then orange-red, erumpent, gelatinous, covered with conidia 

 agglutinated together; conidia elliptic-oblong, continuous, 

 catenulate, 14-18x7-8 ft. 



Removing the shoots on the first appearance of the white 

 spots checks the disease. As the conidia are massed 

 together by a gelatinous substance, they are probably washed 

 from one twig to another by rain, or carried from one tree to 

 another on the feet of birds, etc. 



Massee, Kew Bulletin, 1898, p. 19. 



PENICILLIUM (LINK.) 



Mycelium creeping, septate ; fertile branches erect with 

 branchlets arranged in irregular verticils near the apex; 

 conidia produced in chains, hyaline or clear coloured. 



Distinguished by the branchlets of the conidiophores being 

 grouped in irregular whorls or in a penicillate manner, and 

 the long chains of globose or elliptical conidia. 



Orange rot. Samples of rotten oranges received from 

 Natal, Cape of Good Hope, etc., are from time to time sent to 

 Kew for investigation. Some of the specimens are completely 

 rotten on arrival, others more or less so, while some only 

 show a very soft patch without any trace of mildew. In 

 every instance the injury is found to be due to Penicillium 

 italicum (Wehmer), which acts as a wound-parasite. In all pro- 

 bability the fungus is present in abundance on decaying fruit 

 in the orange groves, and in those places where the fruit is 

 packed, hence the conidia will be present everywhere, and 

 attacks those portions of the rind that have been in anyway 

 bruised or injured. Repeated experiments conducted at Kew 

 prp-ve that the conidia cannot infect the uninjured surface of 

 the rind, but if the smallest bruise is made, one just sufficient 

 to liberate the contents of a few of the large oil cavities 

 in the rind, infection quickly follows. In about a week a 



