255 



the sum of five dollars. The payment of these annual dues shall 

 entitle each active member to receive all publications of the club 

 issued during the year." 



The following papers were presented : 



" Remarks on the Formation of aerial Tubers in Solamim tuber- 

 osum" by Dr. C. Stuart Gager. 



A brief outline was first given of the steps in the germination 

 of the potato seed, up to and including the growth of the primary 

 rhizomes, and the formation at their distal ends of the first tubers. 

 Reference was then made to two recent publications in Torreya 

 (6: i8i, 2 11. 1906), describing an anomalous formation of a 

 tuber of Solanuvi tuberosum, on a sprout from a seed tuber, in 

 daylight, and briefly summarizing the pertinent literature. 



The specimen in question, with photograph, was then exhib- 

 ited, and possible causes of the anomaly discussed. Prunet's 

 researches (Rev. Gen. de Bot. 5 : 49. 1893) led him to the con- 

 clusion that, at maturity, the apical and basal ends of the mature 

 tuber are physiologically different, due to a redistribution, after 

 the cessation of growth, of the reserve materials stored in the 

 tuber while it was forming. The validity of this conclusion has 

 never been tested by other investigators, and it was thought im- 

 probable that such a condition, even if it existed in the seed tuber 

 which bore the anomaly, would enter as a causative factor. 



The specimen exhibited, and numerous other recorded cases 

 of the formation of tubers on aerial branches, render very improb- 

 able the suggestion of Noel Bernard (Rev. Gen. de Bot. 14: 139, 

 269. 1902), and of Jumelle (Rev. Gen. de Bot. 17: 49. 1905), 

 that potato tubers are caused by a fungus, a species of Fusarium^ 

 endotrophic with S. tuberosum. 



In the normal formation of tubers two kinds of factors are 

 doubtless involved : the first organic, consisting of specific 

 peculiarities in the protoplasts ; the second environmental, com- 

 prising external conditions, especially of light and moisture, and 

 the stimulus of the various metabolic products within the stem. 

 The ability to induce tuberization in aerial stems by depriving 

 them of light and reducing their transpiration, as Vochting did, 

 and the sport described by Vilmorin (see Torreya, /. t-.), suggest 



