Varietäten, Descendenz, Hybriden. 521 



hybrid between the varieties ''Volga Russian" and "Curled Savoy". 

 The hybrid was very vigorous and grew rapidly. The leaves are 

 in size and shape nearer to the cabbage, in colour a mean between 

 the light green of radish and the dark or blue green of cabbage, 

 in taste more like cabbage, but somewhat pungent like radish, gla- 

 brous like cabbage, etc. The hybrid has an open, diffuse growth 

 habit as radish, does not develop a tuberous root, but continues to 

 develop numerous large leaves, etc. For further detail vid original. 

 Nearly every day during March, April and May, pollen from 

 different varieties of radish and cabbage, including the parents, 

 and from cauliflower, colJards, Brüssels sprouts and their crosses, 

 was tried on the flowers of the radishcabbage hybrid, but nothing 

 resulted. The hybrid was also sterile to its own pollen. Flowers of 

 the radish, cabbage and various Brassica crosses mere emasculated, 

 bagged and pollinated without results. The same process of polli- 

 nation was gone through in the winter of 1912 with a root cutting 

 of the hybrid and again resulted in failure. 



M. J. Sirks (Haarlem). 



Grifflths, D., "Reversion" in prickly pears. (Journ. of Here- 

 dity. V. p. 222—225. 1914.) 



In the cultivation of prickly pears {Opuntia lindheimeri) it is in 

 San Antonio region necessary for one to choose between the spi- 

 neless forms not needing singeing and the much more productive 

 spiny native varieties, which are not only dißicult but often impos- 

 sible to singe properly. It may be possible in time to breed varie- 

 ties better adapted than the native ones, but the development of 

 such forms from the spiny native prickly pears of the delta of the 

 Rio Grande is an almost hopeless task, the Variation in the 

 number of spines produced being so trifling as to scarcely Warrant 

 selection, while they do not appear to hybridize readily with the 

 spineless forms. 



In 1905 a few cuttings were imported in America from 

 Malta, belonging to the nearly spineless Opuntia fictis indica. In 

 the planting of this stock it was noticed, that one side of one plant 

 of this number was very spiny and the other side as spineless as 

 the remainder of the importation. All new growth on one side of 

 the plant, whether from the original cutting or from a younger 

 Joint, was practically spineless, while the other side was exceedingly 

 spiny, the latter resembling the more common forms of prickly 

 pears and bearing two to four white spines two-thirds of an inch 

 to one and one-half inches long. 



The habit of reversion or bud Variation whichever it may be 

 considered, is a very important characteristic, and, while more 

 striking in the above variety than any other which has been culti- 

 vated in these investigations, appears to be not at all uncommon. 

 A plant of another spineless variety started to vary in the same 

 direction in 1913. 



Both of these variations appear to the writer to point to the 

 origin of the spineless species of the so-called ficus indica group 

 from the spiny ones. the spineless forms being the result of a long 

 series of selection. The striking Variation of certain spineless forms 

 to a spiny condition is looked upon as a reversion to an original type. 



M. J. Sirks (Haarlem). 



