124 



THE GARDENERS' CHRONICLE. 



[February 24, 1912. 



Presentation Cup for the Royal Inter- 



national Exhibition. 



A most successful 



ting of the Horticultural Club took place on 

 Tuesday last at the Hotel Windsor, Westminster, 

 in connection with the annual dinner. During 

 the proceedings, which we shall describe more 

 fully in our next issue, Sir Frank Crisp, the 

 new president, announced his intention of offer- 

 ing a cup, value £25, for presentation at the 

 Royal International Show to be held in May 

 next. The cup will be offered in the name of 

 the Horticultural Club. 



SOLANUM TUBEROSUM \ A TRUE SPECIES. 



The botanical origin of the Potato has been the 

 eubject of much speculation and discussion, but, 

 as is so often the case with cultivated plants, 

 little certain knowledge has been gained with 

 respect to it. As the result of a long and careful 

 investigation, involving a study of the anatomy 

 and morphology of the chief cultivated varie- 

 ties, Mr. P. Berthault concludes that they 

 are all derived from a common ancestor, and 

 that that ancestor is not any of the known wild 

 tuberous solanums. We are driven, therefore, 

 to conclude that our Potatos are varieties of a 

 true species of S. tuberosum, the wild form of 

 which is now either very rare or extinct. 



Toxic Excreta of Plants. — Experiments 



made by Mr. Fletcher, the result of which 



are published in the Journal of Agricultural 



Science, appear to confirm the view r s previously 



expressed by the author and other writers 



that the roots of plants excrete substances 



which are, or may be, poisonous to other 



plants. The experiments in question were 



carried out at Gizet, Egypt, where the 



rainfall is practically nil and where, therefore, 



the water supply is under complete control. 



Maize and Sesamum w T ere grown in alternate 



rows. Certain rows w r ere watered at intervals, 



Borne every 15 days, others every 10 days, 



and others again every 2 days, and certain 



of the last-mentioned were manured every eight 



days with small quantities of sodium nitrate, 



potassium sulphate, and sodium phosphate. In 



every case the Sesamum, which was planted at 



about 1^ foot from the Maize, developed very 



badly. This poor development was as marked 



in the manured rows as in the non-manured. 



Mr. Fletcher concludes that the poor growth 



is due not to lack of food materials, but to 



actual poisoning of the roots of the Sesamum 



by excreta from the Maize. 



HOME CORRESPONDENCE. 



(The Editors do not hold themselves responsible for 

 the opinions expressed by correspondents.) 



Correction : R.H.S. " Journal." — In the 



report on Sw r eet Peas at Wisley, 1911, at p. 394 

 of the Journal (vol. xxxvii., pt. 2) the last sen- 

 tence in the opening paragraph has been trans- 

 posed. It should, as the report itself shows, come 

 after the words " Several varieties were also re- 

 commended on account of their strong growth, 

 and because of their non-burning qualities. They 

 are indicated by the sign P below. These varie- 

 ties . . . ." etc. W. Wilts, Secretary. 



The R.H.S. Annual General Meeting. — 



I have just returned from the meeting in the 

 Royal Horticultural Hall, and have the uneasy 

 feeling that I might have put the time to better 

 use. I sat at the back of the small gathering, 

 and, except for the remarks of the president and 

 treasurer, I know but very little of what was 

 said. Judging from the appreciative attention 

 of those near him, Mr. Engleheart made a 

 thoughtful and interesting speech, but practically 

 none of it filtered to the back benchers. No 

 one who has heard Mr. Engleheart speak will 

 for one moment lay any blame on the speaker, 

 for he has an enviable voice and delivery. It 

 seemed to me that the greater portion of his 



remarks were absorbed by the red curtain be- 

 hind the chairman. It was evident that others 

 besides the writer suffered in this respect. One 

 Fellow put the time to good use by adopting the 

 attitude one associates with prosy sermons; 

 others looked listless and " out of it." I would 

 suggest to the Council that at their future meet- 

 ings they adopt the plan of some other large 

 bodies (the National Rifle Association, for in- 

 stance), and request speakers to address the 

 meeting from the platform. A Fellow. 



Games in Public Parks. — I was interested 

 in the paragraph on p. 105, respecting the num- 

 ber of games played in the London County 

 Council parks. The statistics show that 15,558 

 games of bowls were played on 100 greens. We 

 have recently made two bowling greens in the 

 Victoria Park, Widnes. The first was opened on 

 Easter Monday last, the second a month later, 

 and both were closed on September 28. During 

 that period 13,972 games were played, which is 

 only 1,086 fewer than on the 100 greens of the 

 L.C.C. parks, and the fees amounted to 

 £101 10s. 3d. Is this a record? H. Curtis , 

 Victoria Parle, Widnes. 



Colouring of Apples. — In my note on 7 p. 59 

 I omitted to state, with reference to the experi- 

 ment I described, that both the trees which were 

 allowed to send one or two tap-roots into the 

 chalk and those which were not allowed to do so 

 were root-pruned, so that the greater amount of 

 colour produced in the fruits from trees which 

 had a tap-root in the chalk must have been due, 

 in some manner or other, to the influence of the 

 chalk. Wm. H. Johns. 



Spraying for Big Buds. — In reply to 



Mr. A. H. Pearson (see p. 106), one of my 

 objections to all methods of spraying that I have 

 seen is that they could not be effectual, because 

 they extended over only about half the period 

 of the migration of the mites. Probably Mr. 

 Pearson's period of spraying is longer, and if 

 he would give details in your columns of the 

 dates, and number of sprayings and the 

 strength of the wash used, it would be less 

 trouble to him and would be read by a much 

 greater number of persons than would be the 

 case if he follows up his obliging offer of giving 

 particulars privately to all who ask for them. 

 " Nothing succeeds like success," and if an in- 

 fested plantation is cured by Mr. Pearson's 

 method there is no more to be said, although I 

 am at a loss to understand how that success is 

 attained. If my memory serves, the mites are 

 migrating daily for eight or nine weeks, and it 

 is clear therefore that not a tenth part of them 

 can be killed by contact by spraying three or 

 four times. Is it supposed that the coating of 

 the buds with the spray-stuff deters mites from 

 entering them? I have 27 acres of Black 

 Currants as bottom fruit, and the expense of 

 spraying them three or four times would be 

 heavy ; but if Mr. Pearson will kindly give in 

 your columns the details of his plan, I will try 

 it this season on one piece and give the results 

 next season. (See Gard. Chron., May 21, 1904, 

 p. 330, Eds.}. But my plan of picking off all big 

 buds annually where there are only a few on a 

 bush, cutting off badly infested shoots, and 

 cutting to the ground level a badly infested 

 whole bush has left my plantations approxi- 

 mately free from mite. In the oldest one, 

 8g acres, planted partly six and partly seven 

 years ago, the experienced pickers got only 

 about three pints of big buds last week. The 

 cost is trifling, and only experience would con- 

 vince me that I could get equally good results 

 by spraying. As for the incidental advantage 

 of cleansing the bushes of aphis when spraying 

 for mites, I have tried spraying with a very 

 strong ^ decoction of quassia and soft soap for 

 that direct purpose, and have failed to effect 

 anything like a clearance. Some of the pests 

 are killed, but there are enough left to make up 

 for the mortality in a few days, so rapid is their 

 multiplication. Perhaps this is because I have 

 a patent Black Currant aphis of my own, which 

 no one appears able to identify. It resembles 

 the black dolphin to the naked eye, but 

 of an olive-green colour as seen through 

 magnifying lens. It attacks the tops of young 

 shoots, and at once causes the top leaves to 

 curve over it, umbrella fashion, so that it is to 

 a great extent protected from spray fluid. I 

 encounter it effectually, however, by sending 



is 

 a 



women over the plantations two or three times,, 

 at fortnightly intervals, with small pots con- 

 taining quassia and soft soap, in which they dip 

 and shake about every infested shoot. I have 

 never been troubled to any extent worth notice 

 with the common Currant aphis, perhaps 

 because my bushes are not at all crowded. A 

 Southern Grower. 



Cinerarias Seeding.— In "Answers to Cor- 

 respondents" columns, p. 96, it is stated that 

 " great difficulty is experienced by most growers 

 in obtaining seeds true to variety from these 

 plants, as the plants cross-pollinate so freely.'* 

 Having made a very large number of Cineraria 

 crosses and self-pollinations extending over a 

 series of years, I may strengthen that statement 

 by saying that no seeds are ever produced except 

 by cross-pollination. Reference was made to a few 

 hybrids which are sterile with their own pollen, 

 but I would say that not only are all the plants 

 of all hybrids sterile with their own pollen, but 

 every plant of every species of Cineraria yet intro- 

 duced is absolutely self-sterile. It is not true of 

 all hybrids, but it is true of some hybrids, C. 

 Lynchii, for instance, that they produce seeds but 

 sparingly, with all the trouble of crossing that 

 may be taken. This hybrid, in fact, when 

 wanted, should be remade from the parents; it 

 is easy to procure, and the plant, when well 

 grown, is a very fine one. It is C. multiflorus X 

 Garden Cineraria, and by taking good forms of 

 the garden Cineraria, fine vigorous plants may be 

 obtained with beautiful flowers. The crossing of 

 Cinerarias is easily effected. I have had hy- 

 brid plants that have combined all the species of 

 Cineraria in cultivation at the time, not omit- 

 ting the garden Cineraria. A brush is not neces- 

 sary, the best plan being to take a flower- 

 head on which there is ripe pollen by 

 its stalk between the finger and thumb, and pass- 

 it over the heads, when it is seen that the 

 female organs are in a receptive condition. 

 A smooth thumb-nail can, in many cases, be used, 

 when the stigmas project, for the purpose of 

 transferring pollen to the stigmas with much 

 greater facility than a camel-hair brush. Better 

 again than a camel-hair brush, when the stigmas 

 do not project, and always far more economical of 

 pollen is an anther with the pollen taken by its 

 stalk between the points of fine forceps. Has 

 any reader, after making careful experiment, 

 found any Cineraria that was not self -sterile? I 

 must admit that exception is possible— that a 

 thousand plants might be sterile and the first of 

 the next thousand self-fertile, and also that there 

 might be conditions that would render fertile, 

 plants that are normally self-sterile. Informa- 

 tion of such conditions with regard to any self- 

 sterile plant would be welcome. We know the 

 object of self -sterility, but we do not know what 

 it consists in or how it is attained. One of my 

 reasons for making definite assertion of selt- 

 sterility in Cinerarias is that few realise the tact 

 of its existence in any plant, though it is not 

 rare, being found in quite diverse natural Orders, 

 and is quite common in the Composite. A 

 writer in America, for instance, who has dis- 

 covered a method of depollination for use when 

 the plant's own pollen has reached the stigmas, 

 gives the special instruction necessary for de- 

 pollinating Cinerarias, and the process in that 

 case, according to my experience, is quite 

 unnecessary. R. Irwin Lynch, Botanic Garden, 

 Cambridge. 



Sweet Pea Disease.— The articles by W.pn 



the above subject raise the whole question 

 of "streak" in Sweet Peas to a promi- 

 nent place in the Gardeners' Chronicle. Many 

 hundreds of Sweet Pea lovers will have 

 read the notes with interest and perhaps 

 profit. I think, however, that the matter is 

 not to be disposed of in the easy manner that \\ • 

 seems to indicate. Some 23 years ago I began to 

 grow Sweet Peas systematically in quantity, 

 sowing in November, December, and January, 

 in small "60" pots, five to seven seeds .in 

 a pot, getting them through the soil q uick ^ 

 and then giving all the air possible. *>> 

 February, the lights were taken away, and 

 pilchard netting was tacked over the cases, whicn 

 was kept up by laths from off the Peas, 

 usually confined myself each season to 14 distinct 

 varieties. Generally drifts of 3 feet wide were 

 trenched through during the winter in the posi- 

 tions where the rows were to be. During some 

 time in February, or, in late seasons, early 























