May, 1910.] 



440 



Miscellaneous, 



a most interesting and important sub- 

 ject of enquiry. While the actual 

 manner in which species are produced 

 in Nature may differ, and it probably 

 does differ in details, from that in 

 which varieties are produced in horti- 

 culture, yet the laws governing the 

 process will be the same in both cases. 

 In "fixing" the varieties which arise 

 in the garden, there is generally the 

 difficulty of guarding against cross-polli- 

 nation, since numerous closely-allied 

 forms are usually cultivated in close 

 proximity to the new form, and there 

 is the fact that many of the variations 

 it is desired to reproduce and develop 

 are only faintly indicated at first, as 

 in the cases of doubling of flowers or 

 variegation of foliage. Only after care- 

 ful selection and constant care do such 

 variations become so marked as to en- 

 sure a sufficient contrast with the species 

 from which they were derived to make 

 them worth cultivation as novelties. 



There are thus two types of varieties 

 with which the horticulturist has to 

 deal — the "constant" variety and the 

 " ever-sporting " variety. The former 

 type, Prof, de Vries calls "mutants," 

 and in reply to a question, pointed out 

 that "mutants" differ from other vari- 

 ations, fluctuating variations as they 

 may be called, in that the former arise 

 suddenly and not by small degrees, and 

 when they have once appeared they 

 "breed true" to their new characters 

 provided they are self-pollinated, while 

 varieties formed after the tedious, oft- 

 repeated selection of small differences, 

 differences depending very often upon 

 methods of cultivation, belong to the 

 "ever-sporting" type. 



Good examples of " Mutants " are 

 furnished by white "sports" of many 

 flowers and by dwarf varieties. With 

 these the florist's work in fixing lies 

 in securing isolation, and if isolation 

 be complete, theflxirg is accompalished 

 in a single year. 



The extent and even the occurrence 

 of variegated Horse Radish depends 

 largely upon the method of cultivation, 

 and, the extent of doubling seen in 

 other plants may vary enormously even 

 on a single plant at different seasons of 

 the year. These afford examples of the 

 ''ever-sporting" varieties. Such vari- 

 eties may arise fully developed or may 

 appear only by steps. Small indications 

 of possibilities appear first, and the 

 florist has to isolate them and " work 

 them up "by constant selection of the 

 most marked variations in the desired 

 (jirection. 



The lecturer then went on to show how 

 varieties have been produced under hid 



own observation in plants who3e his- 

 tories had been known for many 

 generations. 



His first example was the peloric form 

 of the common Toad Flax. This form 

 has, in all its flowers five spurs, instead of 

 only one spur as seen in the common 

 type. It has been found in a considerable 

 number of widely-separated places under 

 circumstances that leave no reasonable 

 doubt that it has been produced from 

 seed of the common type It rarely 

 produces seed, but, being perennial, is 

 able to hold its own for a considerable 

 number of years, though it may finally 

 disappear. Prof, de Vries sowed seed of 

 the . common type in his garden and 

 watched the progeny through eight 

 generations, always excluding the chance 

 of cross-fertilisation, without observing 

 any change whatever. In the ninth 

 generation, however, a plant bearing 

 peloric flowers suddenly appeared. Thus 

 a sudden variation had occurred under 

 his own observation without any pre- 

 vious indication of deviation from the 

 type. The seed he was able to save from 

 this abnormal specimen reproduced the 

 variation, and similar variations had 

 arisen from succeding generations at 

 intervals. 



In like manner he had seen sudden 

 variations arise in CEnothera biennis, 

 where a form with very narrow petals, 

 which he had called " cruciata," had 

 appeared, and in the Dahlia, where the 

 tubular corollas were darkly coloured 

 inside instead of outside, as is usual. 



As an example of an "ever-sporting" 

 variety, the lecturer gave an account of 

 the experimental development of the 

 Double Corn Marigold (Chrysanthemum 

 segetum), since double flowers of Compo- 

 site form an excellent example of " ever- 

 sporting " variations. 



The seed in this case was derived from 

 the large-flowered garden variety, in 

 which there are on an average twenty- 

 one rays, though the range of variation 

 in number is up to twenty-four and 

 down to nine. In the fourth year, by 

 selectiug flowers showing the largest 

 number of rays each year, the average 

 was raised to about one hundred. 

 It might have been expected, said the 

 lecturer, that the average number of ray 

 florets might beincreaspd by this process 

 of selection, but there was also the 

 chance that a double variety might be 

 secured, and this was actually the case, 

 for in the fifth year one was secured in 

 which about two hundred rays were pre- 

 sent in the head. Thus, by selecting what 

 was at first a slight variation from the 

 normal, and breeding from those of its 



