24 



THE GARDENER'S MONTHLY 



[January, 



stand difterently. At a recent meeting of the 

 Scottish Arboricultnral Society, Mr. M'Corquodale 

 said he had measured recently two specimens of 

 Abies Douglasii, which were 41 years of age. One 

 contained OOj cubic feet of timber, and the other 

 132 cubic feet. That was a rapidity of growth in 

 coniferous trees that was seldom seen. Douglasii 

 was suited by a dry soil remarkably well. 



QUERIES. 



Depth of Roots. — J. B. says: "You remark 

 that the roots of trees which run deep are not 

 for food, but for moisture. Is it a recognized 

 truth in vegetable physiology that some roots 

 can only take up moisture, while others can take 

 other kinds of food?" 



[We have never said that some roots can take 

 up moisture onhj, but it is tolerably certain that 

 young active fihrrs supply the plant wath nutri- 

 tive matter, while roots, that is (speaking of 

 trees), fibres that are more than a year old, do so 

 only with difliculty. Trees that lose their fibres 

 by rotting, or by fungi, have but yellow foliage, 

 and weak growth. They can take something 

 from the soil through these main roots, but not 

 what the fibres can. As to the fact, Mr. Darwin 

 says that Drosera roots can take in only water ; 

 and then we know practically that the roots of 

 the trees which go deep down into the subsoil 

 do not take up more than moisture, because 

 there is nothing else often ip the poor subsoil to 

 take. Plant food is chiefly at the surface.— Ed.] 



Aponogeton distachyon. — " Please let me 

 know, through the Gardener's Monthly, the botan- 

 ical family and native place of the water plant 

 called by the gardeners "Aponegeton dis- 

 tachyon." 



A [native of Cape of Good Hope, and, let us 

 say, one of the most interesting flowers to have, 

 and one of the easist to cultivate. Last year 

 we had a flower given to us by Mr. W. T. Foust, 

 of Philadelphia, from a plant that was raised, 

 simply in a tub of water— it being an aquatic. 

 It is of the natural order Juncaginace:^. The 

 white flowers are curiously formed, but the in- 

 describably sweet odor is its chief charm. It 

 would, we think, be hardy in any water where the 

 ice did not reach the bottom. — Ed. G. M.J 



The Potato Disease.— M. .says: ''Dear Sir:— 

 Since my return from Europe, where I spent the 



summer, I have been looking over some of the 

 back numbers of the Gardener's Chronicle, and 

 find that the potato rot continues* to excite spec- 

 ulation. You have doubtless often seen a lot of 

 English gooseberries, with a mild spring make 

 some nice young wood of several inches long, 

 when one night's frost would come, which would 

 not only check up the growth of the young 

 shoots, but in a few days you would find both 

 the shoots and the young berries covered with a 

 leathery fiuigus which enclosed them as a coat 

 of mail, and which you, sir, knowing well what 

 was the cause for that fimgus being there, would 

 count it idle to inquire further whether it was a 

 spore or a fungus. During my several crossings 

 of the Atlantic I have always spent a few weeks 

 in fatherland (north of Ireland), where, in an- 

 swer to my many inquiries as to the potato rot 

 and its cause, I was always invariably told that 

 the rot was preceded by a heavy fog, that ap- 

 proached the land from the east, and that as soon 

 as the fog passed away, the potato leaf would be 

 limp, and get discolored, and should the sun 

 come out strong, would throw off" a very disagree- 

 able odor. I was in Ireland during the potato 

 rot fog last August (1875). For some days after- 

 wards you could have smelled the potato fields 

 at a considerable distance. Tlie fog passed over 

 the north of Ireland about the 15th of August, 

 and in a conversation with a friend who plants 

 12 to 15 acres potatoes annually, he told me that 

 he had passed through his potato fields at early 

 morn, before the fog had passed away, and that 

 every leaf was frozen stiff. 



" Since my return home I passed one evening 

 a beautiful flat of Dahlias belonging to my sons. 

 Two days afterwards, upon passing the same flat 

 of Dahlias, it reminded me of an Irish potato 

 field stricken with the potato rot, and there waa 

 no perceptible difference in the smell. Frost 

 did it. M." 



[Nothing is more clearly proved than the fun- 

 goid origin of the potato disease. An examina- 

 tion of the evidence given in back volumes of the 

 Gardener's Monthly and other magazines shows 

 this. The potato disease will often rot a whole 

 cellar full of tubers, when certainly no frost en- 

 tered there. The point made by our corresj^on- 

 dent that last year the disease appeared with 

 most virulence in Ireland after a heavy fog, is a 

 good one, for it has been shown by the observa- 

 tions of Worthington Smith that the form of 

 fungus so destructive last year requires consider- 

 able moisture for its development. — Ed. G. M.] 



