THE PEPPER TREE (SCHINUS MOLLE) IN ITS RELA- 

 TION TO EPIDEiMIC HAY FEVER: INTERIM REPORT. 



By Prof. George Potts, M.Sc, Ph.D. 



For several years past epidemic hay fever has been very 

 prevalent in Bloemfontein and many other up-country towns, and 

 the Pepper Tree is commonly held responsible for the disease. 

 In Bloemfontein the epidemic attacks such a large proportion of 

 the population, especially in early summer after windy weather, 

 and causes so much discomfort and even misery; and the belief 

 that the Pepper Tree is to blame is so widespread, that the Town 

 Council considered the advisability of eradicating the tree from 

 the town, and in December, 191 7, circularised the local 

 medical practitioners for an expression of opinion as to whether 

 the Pepper Tree is to blame for the epidemics. Two doctors 

 were strongly of opinion that the Pepper Tree is the main cause 

 of the disease, whilst five considered that it might be one of 

 many causes, but pointed out that the matter had not been 

 adequately investigated, and that it would be extremely in- 

 advisable to remove a tree which does so much to beautify the 

 town, until the case against it has been definitely and scientifically 

 proved. 



Dr. Targett Adams, ^I.R.C.S., D.P.H., Assistant Medical 

 Officer of Health for the Union, suggested I should investigate 

 the question, and I am also indebted to him for guidance and very 

 material assistance during the course of the investigations. As it 

 is a matter which concerns the Public Health, he himself, and his 

 Department, are vitally interested in it. 



Examination of Floivers. — As a first step the flowers were 

 examined ior the purpose of ascertaining whether the pollen is 

 carried from flower to flower by the wind or by other agencies. 

 It is well-known that there are two sexes in the Pepper Tree. 

 The fruit-bearing, or female, tree bears only female flowers, 

 These have a prominent honey-gland, a pistil with three viscid 

 stigmas, and ten stamens. The anthers, however, contain no 

 pollen, and are white and empty — botanically they are called 

 staminodes. The male tree bears onl}' male flowers. These also 

 have a prominent nectary which secretes honey profusely, and 

 ten fertile stamens, whose anthers are filled with golden-yellow, 

 smooth-grained pollen. There is also an abortive pistil. The 

 pollen is very adhesive ; it sticks together in balls, and in a 

 •mature flower the anthers themselves are often stuck together in 

 groups by means of their pollen. Moreover, when pollen is dropped 

 on to smooth paper, or even on smooth clear glass it adheres 

 so tenaciously that it is irripossible to blow it of¥ with the mouth. 

 The pollen, moreover, is not shed from, nor does it fall out of 

 the anthers. If flowering shoots from a male plant be placed in 

 water it will be fotmd that after the anthers open the male flowers 

 drop ofT with the pollen still contained in the anther-cells. The 

 sam.e thing happens to flowers left on the trees : and if the minute 

 white flowers which are to be found under male trees almost all 

 through the summer be examined, it will be found that the 



