210 On budding and gr-af ting the Mistletoe, 



swells out like the extremity of the sucker of a house-fly, or, 

 according to the comparison of Du Hamel, like the mouth-piece 

 of a hunting-horn. The extremity of the radicle having fixed 

 itself to the bark, if more than one have proceeded from a single 

 seed, the embryos all separate from it; and each, putting out 

 leaves at its upper extremity, becomes a separate plant. In the 

 case of the seeds which germinated on the bark of trees in our 

 garden at Bayswater, the embryos had not separated from the 

 seed on Aug. 15., the day on which we correct this proof. 

 When the mistletoe germinates on the upper side of a branch, 

 the shoots bend upwards ; but, if they are placed on the under 

 side, they descend : when they are placed on the side of a per- 

 pendicular trunk, they proceed horizontally, spreading, of course, 

 with the growth of the plant, so as ultimately to form a hemi- 

 spherical bush. The roots of the mistletoe, which penetrate the 

 bark, extend themselves between the inner bark and the soft 

 wood, where die sap is most abundant, sometimes sending up 

 suckers at a distance from the point where the root entered ; and 

 hence Professor Henslow concludes that the mistletoe is propa- 

 gated in the bark or young wood of the trees in which it is 

 parasitically established, in the same manner as those terrestrial 

 plants which, like the potato, possess rhizomata, or underground 

 stems, or suckers, from the surface of which young plants are 

 developed at intervals. The roots of the mistletoe, as the tree on 

 which it grows advances in growth, become embedded in the 

 solid wood ; and hence has arisen the opinion of some, formed 

 from sections of a branch on which the mistletoe had grown for 

 many years, that it not only roots into the bark, but into the 

 wood. This, however, would be contrary to the wise economy 

 of nature, since it could serve no useful purpose to the plant. 

 The effect of the mistletoe upon the tree on which it grows is 

 injurious to the particular bi'anch to which it is attached; and 

 more particularly to the part of it which extends beyond the 

 point from which the mistletoe protrudes. This is easily accounted 

 for, from both the ascending and returning sap being in a great 

 part absorbed by the roots of the parasite, and prevented from 

 circulating properly. As it does not appear that any part of 

 the sap returned by the leaves of the mistletoe enters into the 

 general circulation of the tree, it is easy to conceive that a cer- 

 tain number of plants growing on any branch would, after they 

 had so far injured that branch as to prevent it from putting out 

 leaves at its extremities, occasion its death, as well as their own 

 speedy destruction. Hence, in orchards, the mistletoe is always 

 removed as soon as it appears. The injury which it does is 

 much greater than that effected by other plants which grow on 

 the bark of trees; such as lichens, mosses, ferns, &c. ; which, 

 though commonly called parasites, are, in botanical language, 



