Queries and Ansiioers. 28 S 



beds guarded with the thread, and find the plan answers. It is so simple, and 

 so useful, that Mr. Anderson is entitled to the thanks of all gardeners. It 

 only wants a fair trial. If market-gardeners, who sow great breadths of the 

 ^rassica tribe, as well as other seeds connected with their business, were to 

 employ this method, I have no doubt one half the seed generally used might 

 be saved; the expense of thread auti time in putting it up being comparatively 

 nothing. I should advise the thread to be no more than 2 ft. apart in lines ; 

 and, when the beds are long, to support the line every 3 or 4 yards with 

 slender forked sticks, firmly fixed in the ground. — AI. Wc&twood. Grove, 

 Hammersmith, April 21. 1837. 



Grafting the Mistletoe. — I have just received most important information 

 respecting the grafting of the mistletoe, from iNIr. Pitt. Tiie spaces between 

 the jomts, which botanists call internodia, will not do for grafting; there must 

 be a joint let into the bark of the stock in grafting, or a scion spliced oft' with 

 a heel, as it is called, and the heel inserted. If this should be found correct 

 (and I have no doubt whatever on the point), it is a curious fact gained relative 

 to the nature, constitution, and habits, of this singular plant. There must be 

 some sort of absorbents analogous to the spongioles of fibrous roots, in the 

 joints of the mistletoe, by which it is enabled to draw its vegetable nourish- 

 ment. If the mistletoe is headed down, it will spring out with increased vigour, 

 like other trees. Young shoots, obtained in this way, with a heel of the old 

 wood, and bark attached, would make excellent grafts. The internodia appear 

 to be incapable of producnig adventitious buds ; but any joint of mistletoe will 

 push out after the top is cut oft'. Tiie mistletoe cannot be eradicated from fruit 

 trees, without cutting the bough below its junction, or disbarking the whole of 

 the piece attached to the bough. — D. B. Haffiekl,near Ledbury, Alai/ 8. 1S37. 

 Epiphyllum truncdtum on Percskia aculcdia. (p. 139.) — Mr. Symons of 

 Clowance states, that he finds the Epiphi/llum truncdtum flourish and blos- 

 som well when worked on the Cactus triangularis ; but doubts whether it 

 would do on the Pereskia aculeata or not. I should therefore wish to inform 

 him, that I have seen several remarkably fine plants of the E. 

 truncatum worked on the P. aculeata, and flowering luxuriantly. 

 They do, however, require support above the insertion, as the 

 head is apt, from its weight, to burst the bark, and disunite itself 

 from the stock. The stock is headed down, and a notch cut in the 

 end of it, so as to admit the graft, it being cut in the form of a 

 wedge, (fig. 100.) We have several small plants in the Oxford 

 garden doing pretty well; and at Moor Park, Hertfordshire, 100- 

 there were, in 1834, several very fine large plants grafted in this 

 manner. — W. H. B. Botanic Garden, Oxford, April, 1837. 



Art. IV. Queries and Anstvers. 



The Theory of the Rise and Fall of the Sap in A>cer saccharinum when tapped 

 for its Juice. — You are aware, I presume, that immense quantities of sugar 

 are annually made from the juice of the ^^cer saccharinum in the west of 

 Pennsylvania and New York, with which our forests abound (Professor Kidd, 

 in his Bridgewater Treatise, says " they are cultivated " !) ; and, as it has puzzled 

 me to explain the peculiarities attending the flow of this juice, I have resolved 

 to state them to you. 1. It is as completely locked up by continued warmth, 

 as by frost, and only flows by the alternate operation of these agents : yet the 

 same degrees of heat, even after frost, have not always the same eft'ect. Thus, 

 a warm south wind stops the flowing more than a cool north-west wind. A 

 bracing wind promotes the discharge, and a relaxing wind checks it. 2. The juice 

 flows for twenty-four hours after a frost; but, when a tapped tree has ceased, 

 tap a new tree, and considerable flow will take place, as if a certain quantity 

 were discharged by the frost. The juice flows from all sides of the incision. 

 3. Tap a tree early in the morning, after a cold night, and no juice will flow: 



