THE GARDENERS' MAGAZINE. 



537 



CHRYSANTHEMUMS. 



Taking: Buds of Late Varieties. 



Last year, owing to the great heat 

 lainiy, the bads ot many late chrysanthe- 

 mums that showed at the end of July were 

 very hard. In some instances the buds 

 were so full of petals that they had not 

 room to develop. In normal seasons the 

 first crown buds are splendid, and the pre- 

 sent one will be, I think, a good one for 

 early crowns. 



The experienced cultivator treats the 

 plants of a number of varieties in two or 

 three ways, that is, he has plants bearing 

 first natural crowns, others bearing first 

 crowns from early stopping, and, again, 

 some bearing second crowns. 



If he knew beforehand what the summer 

 season was going to be like he would know 

 exactly how to treat, practically, every 

 variety ; but he does not know, and so he 

 acts accordingly to his judgment. 

 (Many growers will be anxiously watching 



the progress of that splendid white-flowered 

 Japanese, Mrs. Gdbert Drabble. Of 

 course, it is a very late variety, and needed 

 early stopping. The resultant shoots goon 

 appeared as if they were going to bear pre- 

 mature buds, and any cultivator who may 

 have noticed their condition, and, taking 

 alarm, pinched the shoots again, did a 

 wrong thing, as the bud has not appeared, 

 and will not do so before the proper time — 

 early in August 



Last year the variety Frances JoUiffe 

 came almost pure straw-yellow from early 

 crowns, the pink in the petals being very 

 faint indeed. One large grower exhibited 

 some exquisitely coloured blooms from first 

 crowns taken rather late ; the pink in them 

 rather predominated. Mary Poulton was 

 persistent in showing buds, and only good 



blooms resulted from those taken " 

 rather late. Very early ones had many 

 centres. 



I saw blooms of Evangeline last autumn 

 as pink as the old variety Belle Poule when 

 at its best, and in the same stand were 



early 

 to de- 



pure white blooms resulting from 

 buds. It seems to Obe 



seems to loe wrong 

 scribe this variety as white, and it would be 

 risky to exhibit it in a class as such, as 

 nearly all the blooms that I have seen 

 were tinted with rosy-pink. 



I feel quite such that the colours from 

 the first crown buds this year will be much 

 richer than they were last year, simply on 

 account of the cooler season. 



I learn that some growers have put their 

 plants in their flowering pots several weeks 

 earlier than usual, and that so far, the 

 specimens are far more promising than they 

 have been in previous years. I can quite 

 understand this ; too often the young plants 

 are retained too long in the 32's. 



Feeding^ and Top-dressing;. 



I am a firm believer in the top-dressing 

 of the plants in the month of July. jMany 

 cultivators do not top-dress before the buds 

 are "taken," hut this, I consider, is too 

 late, especially in the case of plants finally 

 potted on June 1. If a surface mulch be 

 put on in July another one can be added 

 at the end of August, and there will be 

 many more roots than if only one surface 

 dressing was given after hud-taking. I 

 also believe in feeding according to the con- 

 dition of the plants. The latter should be 

 kept steadily progressing, and I would fee<l 

 at any time if it be necessary. I strongly 

 advise beginners to be careful in the use 

 of nitrate of soda. This year I have seen 

 the bad effects of strong doses. The cut- 

 tings from the old stools did not make satis- 

 factory progress in the propagating frame, 

 3^^nd the plants have not grown out of their 

 sickly condition. Geo. Garner. 



MENDELISM. 



The following is the text of the important 

 lecture on " Mendelism" delivered by 

 J. M. Hector, Esq., B.Sc, before the mem- 

 bers of the North of England Horticultural 

 Society at Leeda^ and is reproduced by the 

 courtesy of the executive. In this lecture, 

 all reference to animals has been omitted. It 

 should be noted^ however, that Mendelism 

 applies to animals as well as plants. 



Every new theory challenges criticism. If 

 it be found of general application, it becomes, 

 sooner or later, part ot the intellectual cur- 

 rency of the age. In the case of Menders 

 theory, however, this acceptance was 

 strangely slow. For the paper was published 

 in 1866, and practically ignored until 1900, 

 when interest in its matter was once more 

 aroused through the re-discovery of the facts 

 by three independent investigators. 



How to account for these years of silence 

 is somewhat difficult. They were not due to 

 lack of interest in the subject; nor were they 

 altogether due to chance oversight. The 

 leading authority on hybridisation in 

 Mendel's time, not only read the paper, but 

 corresponded with its author. Y et the 

 theory left no impression on his mind, for 

 Mendel lived before his age. His standpoint 

 was totally different from that of his con- 

 temporaries, and it required the progress of 

 thirty-five years to enable scientists to grasp 

 the scope of the theory. 



Mendel's Standpoint. 



What then was Mendel's standpoint? When 

 we describe a plant (or animal), we do so 

 character by character. When we say that 

 a child resembles one parent in one feature, 

 the other parent in another feature, we are 

 unconscious Mendelists. For if our state- 

 ment means anything, it assumes that these 

 features have been separately inherited. This 

 was Mendel's position. He looked on plants 

 not as individual units, but as aggregates of 

 characters, each character capable of sepa- 

 rate inheritance. 



To demonstrate this, Mendel crossed varie- 

 ties of peas which differed in one or more 

 pairs of characters. Thus, tall peas were 

 crossed with dwarf; green-seeded peas with 

 yellow-seeded ; smooth-seeded peas with 

 wrinkled; peas with white-coated seeds and 

 grey-coated seeds. Altogether, the inherit- 

 ance of seven pairs of characters was thus 

 tested for several generations. All other 

 characters were for the time being ignored. 



On crossing a tall pea with a dwarf, the 

 hybrids of the first generation were all tall 

 plants, no matter which plant was the seed 

 parent. This tall character was termed the 

 dominant character; the alternative charac- 

 ter, dwarfness, which had (outwardly) no 

 expression, he named the recessive. Mendel 

 then asked himself if the dwarf character 

 had actually disappeared; or whether it was 

 still present, but latent, in the constitution 

 of the hybrids. To solve this, he sowed seed 

 from the self fertilised hybrids, and ex- 

 amined all the resulting plants. He found 

 that the dwarf character must havb been 

 present in the first generation for the &ecx)nd 

 generation gave both tall and dwarf plants. 

 Further, there were three times as many tall 

 plants as there were dwarf. 



Again the question as to the purity of these 

 two sets of plants presented itself. Were 

 the tall and dwarf plants " pure " tails and 

 dwarfs or not (i.e., were they capable of 

 transmitting the alternative characters 

 "dwarfness" and "tallness'')? The seed of 

 these plants was accordingly sown, and the 

 plants of the third generation examined in- 

 dividually. Dwarf plants were found to give 

 rise to dwarfs, and to dwarfs only. Not so 

 with the tails. Some gave rise to tails, 

 but from the seed of the others, tall and 

 dwarfs resulted in the proportion of 3 : 1. It 

 was also found that the tall plants which 

 gave rise to tall plants were only half as 

 numerous as those which gave rise to tall 

 and dwarf. That is to say, the tall plants of 

 the second generation were not identical. 

 Some were pure tall (minus the dwarf charac 



ter), and others, twice as numerous, were im- 

 pure tall (containing the recessive character, 

 dwarfness). In the fourth generation the 

 same phenomena were found. 

 Summarising these results, we find 



TiilT X Dwarf 

 Impure Tall 



i 



J hII (25%) 



Impure Tall (50%) 



n - 

 Dwarf (25%) 



I 1 — r 



TaW Tall Impure TaU Dwarl 



Having established the mode of inheritance 

 in one pair of characters, Mendel extended 

 the principle to the other pairs already men- 

 tioned, and found it to hold good for all. 

 Letting D stand for dominant, R for reces- 

 sive, and D (R) for impure or hybrid domi- 

 nant, we can tabulate the results thus : 



I) X R 



Parents. 



Isr Generation 



D 



D (R) 



R 2nd Genrration, 



I 



I) 

 I 



I 



R 

 I 



1 



R 3rd Generation. 



3 



Explanation of Ratios. 



Mjendol then atbempted to explain the 

 ratio of 3: 1, and succeeded in formulating 

 a theory which fits the facts with great 

 accuracy. He supposed that each character 

 would be represented in the pollen grain 

 and the ovule (the future seed) by a single 

 factor, which for simplicity we may postulate 

 as an actual physical substance. Further, 

 he stated that a pollen grain or ovule could 

 contain either the one factor or the other of 

 a pair, but never both. Also, there would be 

 an approximately equal numlicr of each kind 

 of pollen grain and ovule. In other words, 

 the factors would segregate when the repro- 

 ductive cells form. 



Thus, a tall plant would produce pollen 

 grains and ovules, both carrying the factor 

 for talluess. Similarly the dwarf plants 

 would have pollen grains and ovules contain- 

 ing the factor for dwarfness. On crossing 

 these two varieties a hybrid results with 

 only the one character expressed, the other 

 latent. But when this hybrid produces its re- 

 productive cells the two factors segregate, 

 and pollen grains and ovules form, one half 

 of each carrying the factor for tallness, the 

 other half carrying the factor for dwarfness. 

 We have, therefore, two sets of pollen grains 

 and two sets of ovules, approximately equal 

 in number; e.g., 50 pollen grains with the 

 tall factor, and 50 pollen grains with the 

 dwarf factor; similarly with the ovules, 

 lliese pollen grains fertilise the ovules. The 

 possible combinations are three in number, 

 i.e., Tall X Tall, Dwarf x Dwarf, and Tall x 

 Dwarf. According to Quetelet's " Law of 

 Chance," the combination Tall x Dwarf must 

 occur twice as often as either of the other 

 two provided we are dealing with a sufficient 

 number of individuals. Hence we get the 



proportion 1:2:1. 



If we toss two pennies simultaneously we 

 get one of the three following combinations, 

 head and head, head and tail, or tail and tad. 

 If we do this a sufficient number of times, 

 we shall get the head and tail combination 

 occurring twice as often as either of the 

 others. That is to say, they will fall in the 

 proTiortion of 1 : 2 : 1. The law of chance 

 again determines the proportion. -But in 

 the case of plants, the mating of the tall 

 and dwarf factors results in a plant looking 

 exactly like a pure tall plant, owing to the 

 dominance of the tall character. Hence the 

 proportion appears to be three tall to one 



dwarf. 



Recent Experiments. 



"Within recent years Mendel's experiments 

 have been tested on a large number of plants 

 and animals, and no discordant results ol>- 

 tained. Some of the cases have been found 

 to be of greater complexity than was at one 

 time supposed, and in others, the phenomenon 



