xxiv PROCEEDINGS OF THE ROYAL HORTICULTURAL SOCIETY. 



and when it has entirely vanished they are left in the cell as pale yellow 

 globules. The yellow xanthophyll has, however, been present from the 

 beginning, and the disappearance' of the chlorophyll green has merely 

 rendered it visible. The simultaneous presence of the two colouring 

 matters can be demonstrated in this way. When a number of green 

 cotyledons are steeped in alcohol a green extract, as referred to above, is 

 obtained, and this fluid retains its green colour only so long as it is kept 

 from light. When it is exposed to daylight, or even gaslight, it rapidly 

 loses the green colour and fades to a yellowish tint. Upon examining 

 this spectroscopically it is found to have absorption bands in the blue 

 and violet identical with that of an alcoholic extract made from yellow 

 cotyledons. This fading of the green is seen in the autumnal colouring 

 of leaves, and in an inverse order the slow development of chlorophyll 

 when etiolated plants are exposed to light. These facts, I venture to 

 think, render it necessary to modify Mendel's original conception in this 

 special case, as it is evident that the conception of a factor for green and 

 one for yellow, and the alternative inheritance of each, is hardly in 

 harmony with the facts. As all cotyledons pass through the green stage, 

 and certain only pass through to the yellow, I would suggest that the 

 factor may be not a factor of quality, but a factor which extends or limits 

 development." Commenting upon the foregoing, Mr. Hurst wrote : — 

 " The above note by Mr. Bunyard is a valuable contribution to our 

 knowledge of the nature of Mendelian characters in peas. According to 

 Mr. Bunyard's results, green peas contain invisible yellows at all stages 

 of their development, while yellow peas contain green in the early stages 

 only. A yellow pea may therefore be regarded as due to the presence of 

 a factor which causes the green to fade at an early stage of development, 

 while in the green pea this factor is absent. The Mendelian units con- 

 cerned are therefore not simply yellow and green, as Mendel supposed — for 

 all green peas contain the yellow element as well as the green — but would 

 appear to be rather the presence and absence of a factor which causes the 

 green to fade." 



Hybrid Brassicas. — Mr. Sutton, V.M.H., read a paper, which he 

 illustrated by means of lantern slides, upon "Hybrid Brassicas," giving 

 details of a large number of interesting experiments which have led to 

 important results, although no forms of commercial importance have been 

 produced. It is particularly interesting to note that Brassica Napus 

 (rape) would not cross with B. oleracea (the cabbage, thousand -headed 

 kale, &c), nor would B. Bapa (the turnip and swede) ; and of further 

 interest is the fact that the kales 'Ragged Jack ' and 'Asparagus' kale 

 would not cross with the cabbage group, but crossed with B. Napus, thus 

 indicating that they were nearly related to that species. In all the crosses 

 made, where crossing could be accomplished, the seedlings proved to be, 

 as a rule, somewhat like both parents, and were practically all alike. 

 Reciprocal crosses, however, did not always give identical results, but 

 a question put by Mr. Chittenden elicited the fact that the same 

 individuals were not always used in making these reciprocal crosses, 

 i.e., the seed parent in the one case was not always the pollen parent in 

 the other. In the second generation segregation occurred in every case 

 where it was possible to obtain seedlings (many of the F 1 generation proved 



