526 THE PEPPER TREE AND HAY FEVER. 



anthers are invariably still full of pollen, which is easily recog- 

 nized by its deep g-olden-yellovv colour. 



The conspicuousness and non-green colour of the fiowers, 

 the presence of abundant honey, the sticky pollen and viscid 

 stigmas all point to insect-pollination ; and, indeed, insects are 

 frequently to be seen visiting the flowers. 



The evidence obtained by an examination of the flowers is 

 thus all against the likelihood of the pollen being carried by the 

 wind. Indeed if it were carried one would expect to see it in the 

 air, especially when it is remembered that each of the numerous 

 small male flowers has ten fertile stamens. 



In the Pine, which is wind-pollinated, the pollen can often 

 be seen floating in the air around the trees when the stamens are 

 ripe, and if a branch be shaken when the tree is in flower a 

 veritable shower of sulphur-coloured pollen is produced. The 

 same is true of the numerous other ornamental conifers so com- 

 monly grown in garden and parks. iBut the Pine pollen is dry 

 and powdery and does not stick together, and its carriage by the 

 air is faciHtated by the grains being winged. The flowers are 

 also inconspicuous and have no honey. The Pepper Tree on 

 the other hand is undoubtedly insect-pollinated ; the pollen is 

 sticky, adheres together in balls, and is carried irom flower to 

 flower, stuck to the bodies of insects. 



Hay Fever and Pollen in U.S.A. — Hay Fever caused by 

 pollen is very prevalent in America, and there exists there a 

 society for its prevention, called the American Hay Fever Pre- 

 vention Association. The plants which cause the disease are all 

 wind-pollinated and are mostly common weeds ; and experience 

 has shown that eradication of the pollen-producing plant is the 

 only method of dealing with the disease which has given satis- 

 factory results. The objects of the Association are to educate 

 the public as to the relationship between the weeds concerned and 

 hay fever, and to hring about legislation for the eradication of the 

 weeds. Such an "anti-hay-fever-weed law" has been passed by 

 New Orleans, and since being enforced there has been a great 

 reduction in the number of hay fever cases. 



In an article by Dr. W. Scheppegrell, President of the 

 Association, which appeared in the Scientific American Supple- 

 ment, August 12, 1916, emphasis is laid on the statement that all 

 the nlants whose pollen causes hay-fever in America are wind- 

 pollinated. The majority of the plants implicated, as has already 

 been stated, are common weeds ; and it should be noted that many 

 of these are plentiful in and around Bloemfontein and other 

 South African towns. They are common in back-yards, on 

 vacant erven, along the side of our streets, in sluits, and as weeds 

 on cultivated ground. If their pollen is injurious in America, it 

 is most probably equally so in South Africa, in which case much 

 of our epidemic hay fever may quite well be due to these weeds. 



"^-rasses, which, too, are wind-pollinated, have been shown 

 to cause the disease in America, and the researches of *Dr. Black- 



* I am indebted to Dr. Targett Adams for this reference. 



