LORANTIIACEJE. 191 



time, and is not completed until the plumule begins to be developed. By the time 

 the young plant has a pair or two of leaves, the attachment will be found tolerably firm. 

 Mr. Griffiths, who has written a paper on the genera Loranthus and Visowm, in 

 the Transactions of the Linnseau Society, tells us that on cutting away a portion of the 

 branch on which the Mistletoe had fixed itself and laying bare the included portion 

 of the parasite, he found that the union had taken place entirely between the ligneous 

 systems of both ; the fibres of the sucker-like root of the parasite expanding on the 

 wood of the support in the form of a web foot. There was, however, no interchange 

 of structure between them, neither at this period was there any intermixture of 

 ligneous fibres. As the parasite increases in size, and an additional supply of nut "inient 

 is required, lateral shoots are sent out from the surface, which also penetrate the bark 

 and are precisely similar in mode of attachment to the original seedling shoot. It is 

 a curious fact that the fibres of the later shoots never penetrate further than those of 

 their primitive attachment. In the adult plants the sucker-bearing shoots frequently 

 run to a considerable distance ; many of the stocks being literally covered with para- 

 sites, all of which have sprung from one seed. Mr. Griffiths says : — " I have seen such 

 shoots, which had taken their course along a decayed branch, become reflexed and 

 return in quest, as I may express it, of a part capable of affording nourishment." 



The remarkable exception which the Viscum presents to the general law — that the 

 radicle or root of the embryo shoots downwards and the plumule upwards, under all 

 circumstances, has been confirmed by curious experiments. So certain is it that the 

 radicle of the Mistletoe will turn itself towards the body to which it is attached, what- 

 ever may be the position of that body with respect to the earth, that a cannon-ball, 

 to which Mistletoe seeds were glued on all sides, and suspended in the air, became the 

 point of attraction for all the little radicles to direct themselves towards from all sides 

 of the ball. This property insures their growing upon the branches of trees, to what- 

 ever side they may happen to adhere. It is asserted that a brancli of Mistletoe, if 

 placed in water, has no power of absorbing this fluid itself ; but that when the branch 

 to which it is attached is immersed, then the water is readily absorbed and penetrates 

 into the Mistletoe. The following experiment was performed by De Candolle. He 

 immersed the branch of an apple-tree bearing Mistletoe in water previously coloured 

 red with cochineal, which, penetrating the wood and inner bark of the apple-tree, 

 entered into the Mistletoe, when its colour was even more intense than in the former. 

 It would appear as if these parasitic plants had an elective power, for it is certain 

 that they do not attach themselves to all trees or sbrubs indiscriminately. Mr. Griffiths 

 thinks, however, that they would grow on almost any plant whose duration is suffi- 

 ciently long to allow them to establish themselves. Plants with milky juice seem to 

 be an exception. The seeds of Loranthus have been seen to germinate on a frond of 

 Polypodium. The influence these parasites have on the stock is according to their 

 respective proportions. If they attack a small or weakly tree, they injure it, and per- 

 haps kill it ; but when they attack large vigorous trees, no ill results seeui to follow. 



The Mistletoe is the only green parasite in this country, and often forms a con- 

 spicuous feature in the physiognomy of vegetation on the leafless trees of winter. 



In an interesting paper by Dr. Bull on the Mistletoe in Herefordshire, published 

 in the " Journal of Botany " (No. 24), we have a list of the trees on which the Mistletoe 

 flourishes. As his observations have been very carefully made, we may be allowed to 

 ouote them here. 



" The trees upon which the Mistletoe grows, as far as I have ascertained, are as 

 follows: — Apple-tree (Pyrus Mahcx domeatica) ; throughout the county. Abele-tree 



