F. T. Brocks 225 



13. Cephaleuros sp. 



Although this alga is of no economic importance on rubber as 

 is Cephaleuros on. tea it is interesting to note that an organism of this 

 nature can penetrate the leaves of Hevea, on which it is often found 

 in the form of small brown spots more especially on the uncler-surface. 

 Filaments of the alga grow out from these spots and terminate in 

 groups of sporangia as shown in Plate XXXV, fig. 5. This alga is of 

 common occurrence on the leaves of other plants in .Malaya and is 

 specially abundant on clove in which Ridley (ii) states that it causes 

 a serious disease. 



14. Loranthus spp. 



As pointed out by the writer (6) in a Malayan publication, two 

 kinds of Loranthus occurred as semi-parasites on the branches of old 

 rubber trees in a few estates in Negri Sembilan and in one or two areas 

 some damage was being done by them. Bateson (4) has also recorded 

 the presence of a species of Loranthus on rubber in Pahang. In the 

 Negri Sembilan estates, portions of branches beyond the place of 

 attachment of the parasites were often killed. The trees most severely 

 affected were generally in poor condition, being badly burred and 

 having been overlapped some years before. The foliage was thin 

 and this circumstance probably assisted the parasites to become 

 established, for in trees possessing a vigorous leaf canopy the shade 

 cast by the crown tends to prevent the establishment of these trouble- 

 some plants. The development of Loranthus on a rubber tree is a drain 

 upon its resources, and if such "mistletoes" are allowed to develop 

 with impunity the tree will become impoverished, just as apple trees 

 in some parts of England are weakened by the unchecked development 

 of Vise inn album. 



All branches of rubber trees affected by these growths should be 

 cut back well beyond the region to which the parasite extends. 



Various species of Loranthus are of common occurrence in Malaya 

 on many kinds of trees and shrubs. One of the species found on rubber 

 trees grows frequently on Melastoma malabathrieurn, which is one of 

 the commonest wayside shrubs in Malaya. The species of Loranthus 

 seen on rubber trees are provided with runner-like processes which 

 creep along the branches of the host giving off suckers here and there 

 which form the means of attachment and the channels by which food 

 substances are obtained. Some of the suckers become much swollen 



Ann. Biol, n lr * 



