Queries and Answers. 691 



the trees at Farnham Castle (p. 503.), you noticed "a female black Italian 

 poplar," a seed catkin of which had stuck upon an adjoining tree, and on ex- 

 amining which, you found it contained a large quantity of cotton, which you 

 have sent to Manchester. There is a large female poplar here, which pro- 

 duces vast quantities of cotton every season ; so much so, that the shrubs 

 within a great distance of it are disfigured by its downy catkins, and the walks 

 have often to be swept during the season of their falling, to prevent the littery 

 appearance occasioned thereby. This is the Populus monilifera, Canada: is it 

 the same that you call the black Italian ? On looking into your Hortus Bri- 

 tannicns, I find that P. dilatata alone is marked as a native of Italy. You state 

 that the female black Italian is rare, and that you know of only one other spe- 

 cimen, which is in the garden of the London Hort. Soc. If this be the species 

 to which you allude, it will be another added to your number. You saw the 

 tree when you called here (Oct. 13.); but, as I had not then read the interest- 

 ing notes of your late tour, I did not direct your particular attention to it. — 

 James Loudon. Mr. Gurney's Cottage, Upton, Oct. 13. 1835. 



Populus monilifera, though a native of America, is, without doubt, the 

 species called in the nurseries the black Italian poplar ; but how it has come to 

 be °so named, we cannot tell. In Brown's Sylva Americana, it is said to be 

 called, in America, the Vii-ginian poplar, and the Swiss poplar; "the last of which 

 denominations is owing to its being abundantly multiphed in Switzerland," 

 (^Sylva Amer., p. 256.) There is the greatest confusion in the genus Populus 

 in the British nurseries. In our opinion, they may all be reduced to four spe- 

 cies, or, if the term is hked better, four subgenera : P. alba ; P. grse^'ca, which 

 includes tremula, tremuloides, grandidentata, &c. ; P. balsamifera, which in- 

 cludes the Ontario poplar, and all having very resinous buds ; and P. nigra, 

 which we conceive to bear the same relation to P. monilifera, angulata, &c., that 

 a crab does to an apple. The Lombardy poplar we conceive to be a mere sport 

 of P. nigra : but we have written to a friend in Lombardy, to procure us, if 

 possible, the history of the tree in that country. P. cordatawe conceive to be 

 a stunted tomentose variety of the Ontario poplar. These opinions, however, 

 are not to be considered final on our part, till we examine into the subject 

 farther. — Cond. 



Reddish circular Scales on the under Side of Oak Leaves. — Early in the sum- 

 mer, I observed that the under side of the leaves of the oaks had reddish circular 

 spots upon them, which I attributed to insects, and thought no more of them. 

 But, as the season advanced, I observed they altered in their appearance, and 

 I was induced again to examine them under a magnifier, and I came to the 

 conclusion that they were parasitic plants, and not the effect of insects. I 

 thought I could perceive the surface covered with anthers, such as are to 

 be seen on stones that are producing lichens and mosses. The external 

 appearance of one detached from the leaf was not unlike " sun dew." I 

 observed, too, that they were endued with a considerable elastic power ; for, 

 upon inserting the thumb nail under the outward edge, the plant sprang up to 

 the height of 2 in. or 3 in., and darted forward 6 in. or 7 in. This power of 

 dissemination, I need not tell you, many plants possess by contrivances won- 

 derful and most curious. « 



I enclose some oak leaves with these substances upon them ; and I hope 

 they will reach you without being rubbed oiF. I also inclose a few of the 

 plants taken from leaves. 



The oaks, for more than ten miles round, were similarly affected. I do not 

 recollect having ever seen them before. Being at Bagshot Park, I called the 

 attention of Mr. Toward to them, who had noticed the appearance, but con- 

 tented himself with the notion, that they were only discolorations from insects ; 

 but, upon my putting a leaf and a magnifier into his hand, he came over to my 

 opinion. You will observe that the upper surface of the leaves is black and 

 dirty. That appearance preceded the appearance of the spots on the under 

 side, and, perhaps, may be ascribed to honey dew. — W. Lowndes. London, 

 Sept. 2. 1835. 



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