chap. lxii. lorantha v cea:. fi'scum. 1025 



reached that substance, the point of the radicle 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 iis upper ex- 

 tremity, 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. 15th, 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 perpendicular trunk they proceed horizontally, spreading, of 

 course, with the growth of the plant, so as ultimately to form a hemispherical 

 bush. The roots of the mistletoe, which penetrate the bark, extend them- 

 selves between the inner bark and the soft wood, where the 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 propagated in the bark or young wood of the trees in which it is para- 

 sitically established, in the same manner as those terrestial plants which, like 

 the potato, possess rhizomata or underground steins, 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 con- 

 trary 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 branch to which it is attached ; and more par- 

 ticularly 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 certain 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, epiphytes ; that is, inhabiting trees but not living 

 on their substance. The nutriment which supports epiphytes is derived from 

 the decay of the outer bark, or from the atmosphere. Two experiments remain 

 to be made with the mistletoe : the first is, whether it may be propagated 

 by inserting cuttings in the live bark, in the manner of buds or grafts ; 

 and the second, whether a plant of mistletoe would keep alive the tree 

 on which it grows, after that tree was prevented from producing either 

 leaves or shoots. 



The propagation of the mistletoe in British nurseries has scarcely been 

 attempted : but nothing could be easier on thorns or crab apples, planted in 

 pots for the conveniency of removal. Perhaps, if it were propagated on shoots 

 of the poplar or willow, truncheons of these trees with young plants of 

 mistletoe on them might be taken off, and planted as cuttings, without in- 

 juring the parasite. 



App. i. Other Species of Viscum. 



As already observed, many species of Hscum are described by botanists. Several species, Koylc 

 observes, are found in Bengal and Silhet, in mountainous situations ; and V. verticilliftbruni lloyle, 

 at Mussouree, on the oak. V. clonghtum Dec. is found in the Peninsula, and on the hills of the 

 central range of the Himalayas. 



3 y 2 



