458 Transactions of the South African Philosophical Society. 



" On the Prolongation of the Flowering-period of Tritonia 

 (Montbretia) Wilsoni, Baker." Trans. Bot. Soc. Edin. vol. xix. 



Diels, L. " Die Epharmose der Vegetationsorgane bei Bhus L. 

 § Gerontogece, Engler." In Engler's ' Botan. Jahrbucher,' vol. 

 xxiv., 5, pp. 568-647, with 1 plate. 



The author has studied the morphology and anatomy of the 

 leaves of ninety species of the section Gerontogece of the genus 

 Rhus, with a view to ascertain the relations which exist between 

 the structure of the leaves and the climate of their habitat. He 

 arrives at the conclusion that this group of plants originally came 

 from Western Asia, at first invading Eastern Africa and subse- 

 quently spreading and developing largely in South Africa. 

 Consequently he considers it to be a comparatively recent 

 element of our generally much older flora. 



Erikson, Jakob. "Der Heutige Stand der Getreiderostfrage." 

 Ber. der Deutschen Bot. Ges., xv., 3, pp. 183-194. 



The investigations into the nature and causes of rust on 

 cereals, which Mr. Erikson and Mr. E. Henning have carried 

 on at the Experimental Station of the Agricultural Academy of 

 Stockholm for more than six years, have brought to light several 

 facts which considerably modify our knowledge of this vegetable 

 parasite. In the present article the author gives a summary of 

 their microscopic investigations and of the numerous experiments 

 made year after year in the field and in the laboratory. Some of 

 these experiments were very tedious and elaborate. In one 

 series they cultivated various kinds of cereals in glass houses in 

 sterilised soil and air ; but as, during sunshine, in spite of venti- 

 lators driven by steam, the temperature inside became too high, 

 they finally provided these cultivating houses with double walls, 

 between which water was made to circulate. 



As the rust causes a loss of several hundred thousands of 

 pounds every year to the Colony, the subject is one of the 

 greatest importance to our agriculture. Among other things, 

 the author has proved that there are at least ten different forms 

 of rust on cultivated cereals ; that eight of these forms inhabit 

 only one particular kind of plant each ; that the wheat-rust is 

 one of these eight kinds and does not infect any other cereal or 



