139 



ongi, 1 cm. longi, basi 7-9 mm., lati, reflexi. G-ynophorum 



obi 



8 mm. longum, pilis simplicibus puberulum. Filamenta 11-13, 

 in cupulam vix 1 mm. altam extra puberulam connata, superne 

 0*25-0'75 mm. libera ; antherae vix 1;5 mm. longae. Folliculi 

 compresso-ellipsoidei, supra applanati, circiter 8 cm. longi, 

 5 cm. lati, 4 cm. crassi, apice obtuse umbonati, umbone usque 

 ad 1 cm. longo, tuberculis conicis acutis usque ad 5 mm. longis 

 muricati, pilis stellatis brunneo-tomentelli. Semina 4-8 pro 

 folliculo, late ellipsoidea, compressione angnlata, ultra 2 cm. longa. 

 Testa e stratis quatuor constans, quorum externum crustaceuin. 

 secundum corneum, tertium et internum carnosa. Kndospermium 

 alte bipartitum segmentis plano-convexis embryonem occultantibus. 



Cotyledones foliaceae, ellipticae, circiter 1*5 cm. longae, 1*2 cm. 

 latae, radicula leviter exserta 3 mm. longa. 



The "female" flowers of S. Alexandn have well-developed 

 anthers containing an abundance of pollen, and it is possible that 



they are really hermaphrodite. 



T. A. S. 





Hollow Potatoes.— During the past autumn some diseased 

 potatoes were submitted to Kew for investigation. The potatoes 

 were well grown and externally showed no trace of injury or 

 disease, but when cut open were found to be hollow, an external 

 shell, varying from a quarter to half an inch in thickness, 

 remaining intact. 



In some examples the cavity was quite empty, dry, and lined 

 with a shrivelled mass, suggesting the previous presence of some 

 ■semifluid substance that had contracted and dried up. In other 

 cases the cavity was more or less filled with a glairy, unpleasant- 

 smelling pulp, which on microscopic examination was found to 

 be teeming with nematodes or eel worms. 



A series of sections revealed the fact that the nematodes effected 



an entrance into the tuber through the original point of attaeh- 



the 



ment to its branch. 



Having 



once gained an entrance 



from 

 vascular 



nematodes gradually used up the substance of the tuber, working 



the centre outwards until their progress was checked by the 

 lar zone which lies at some distance within the periphery. 



This zone appeared in every instance to have acted as a perfect 

 barrier to the further extension of the eel worms, hence the tissue 

 lying between the vascular ring and the periphery of the tuber 

 remained uninjured. 







*fe 





i 



Section of Hollow Potato. 



