clxxxiv PROCEEDINGS OF THE ROYAL HORTICULTURAL SOCIETY. 



from eggs which were laid in a tree which had just been felled, or was 

 cut down shortly afterwards, so that the grub was soon obliged to feed 

 on very dry wood, from which it obtained but little nourishment." 



Albinism in Shirley Poppies. — A communication was received from 

 Mr. John Bidgood, B.Sc, F.L.S. which will be found at p. 477. He 

 recognises four forms of albinism in flowers — viz. incomplete, complete, 

 partial, and -local. After giving illustrations of the first three from 

 Orchids, the last was taken from Poppies. The original plant of the 

 Shirley Poppies had a white edging to the petals. It was evident, there- 

 fore, that this plant had a tendency towards albinism. The black blotch 

 has disappeared from all Mr. Wilks's stock, being replaced by white. 

 Other growers have experienced reversion to the black blotch. This is 

 caused by a very strong solution of a dark red pigment contained in the 

 epidermal cells on each surface of the petal, the usual cause of black being 

 dark red overlying green, as on the leaves of Arum maculatum. The 

 colour in the outer portion of the petals was also in the epidermal cells. 

 On applying micro-chemical tests the behaviour of the colours of the 

 two regions in question was very different. Strong sulphuric acid 

 changed the black blotch to pink, brick-red, and orange ; the outer part 

 the same, but passed on to yellow, finally disappearing. Iodine in 

 potassium iodide changed the blotch to port-wine colour ; the outer part 

 slowly faded. Solution of caustic potash changed the blotch to a deep 

 blue, then faded out ; the outer part to greenish yellow, then faded out. 

 Neither of the pigments shows the typical reactions of the cyanic series, 

 and still less of the xanthic. 



Super tuber ation in Potatos. — The following communication was 

 received from Mr. F. C. Davidson, Wickham Bishops, Essex : " M. 

 Bernard propounded the theory, in Rev. Gen. de Bot., that tuberisation 

 was due to the irritation set up by a fungus, and he had found that 

 in the Potato there was a relation between the date of infection of 

 the soil and the date of tuberisation. I would suggest a practical 

 application of this theory." Then referring to Dr. B. Dyer's and Mr. 

 Shrivell's paper on 'Manuring Market Garden Crops,' Journal, vol. 

 xxvii. p. 995, he observes : " Whereas such crops as Cabbages may be 

 grown as well with artificial manure as with dung — indeed, it would seem, 

 better and far more economically — this does not hold true of root crops, 

 especially of Potatos. For instance, in the early varieties the average 

 crop for some years was, from 50 loads of dung, 7 tons 7 cwt. ; from 

 25 loads, 5 tons 14 cwt. ; from (no dung) phosphates and 4 cwt. of nitrate 

 of soda, 3 tons 6 cwt. ; and from the same, with potash, 4 tons 10 cwt. 

 The gap here, though potash fills it up a little, is most striking. If dung 

 be favourable to bacteria, they may infest the soil and promote tuberisation. 

 If this conjecture prove to be a fact, it might have a very great influence 

 on the methods of cultivating root crops." Mr. Worsley thought it im- 

 portant to have the desiccated weight given, as the additional moisture in 

 dung manuring would assist to swell the tubers. Mr. Baker said that 

 Potato crops showed the greatest weight when planted in ground which 

 had been manured with dung the previous season for Cabbage crops. 



Diseased Pear Shoots. — In the spring two or three branches of ' Doyenne 

 du Cornice ' were noticed dying and were at once cut off. Since then several 



