19 



round the point of the radicle, exhibits decided signs of compression, curving 

 round the outline of the Mistletoe tissue. In addition also to the union of the 

 cells of the advancing radicle, it would appear that the larger cells of the disc 

 unite with those of the canibial layer, so that nutriment is supplied to the young 

 plant not only by the advancing root, but also by the whole surface of the disc. 

 The dark green centre of the Mistletoe process sends down a very fine series of 

 cells, slightly darker in colour than the rest, into the substance of the advancing 

 spongiole. 



The word " penetration," which contains the pith of the whole, needs some 

 justification. The seed from which the section just described was made was 

 deposited on the bark of a Magnolia tripctula, a soft wooded tree, on February 

 6, 1869. During the whole of the summer the processes made but little progress. 

 It was during the autumn that the greatest apparent growth took place. At this 

 time the bark of the year might be supposed to be complete. A section made on 

 November 25, 1869, from a seed, deposited at tbe same time with the one alluded 

 to, exhibited no such decided appearance as that described above. 



The seed alluded to contained three processes, all of which germinated. 

 Until the beginning of November they remained convergent, being attached to 

 each other by the tissue of the body of the seed. But at that time, when the 

 substance of the seed had been entirely absorbed, they became separate plants, 

 and parallel, as noticed above. 



The history of the seed ends here, at present. It is to be hoped that 

 further observations and experiments will elucidate new stages, and so dispel 

 the mystery which at present enshrouds the plant. 



Propagation of Mktletoe by Rhizomes.— The Mistletoe plant having once 

 become established upon any given tree, soon begins to increase by another 

 mode of reproduction. This is effected by means of rhizomes, exactly corres- 

 ponding to the underground stems of terrestrial plants. This fact may be 

 commonly seen, but a marked instance of this mode of growth is given by Dr. 

 Bull in his paper on Mistletoe, before alluded to, with regard to the mistletoe 

 oak of Frampton on Severn, where, when it had killed the bough of the tree on 

 which it grew, a fresh plant of Mistletoe shot out from the trunk. To this 

 mode of rhizomatous reproduction is mainly due the abundance of Mistletoe on 

 the trees on which it has once established itself. 



The proof that this is the case may be practically shown. Firstly, on 

 examining the bark of a branch occupied by Mistletoe, small protuberances of 

 the peculiar mistletoe green colour may be found. These break out with no 

 regular dehiscence : a leaf-bud is at once developed without any traces of the 

 two cotyledon leaves. Secondly, the young plants, found in such numbers on 

 the trunks of old apple trees, cannot always be due directly to seeds. They 

 may be dug out with fully half an inch of dead dry bark above the surface of 

 the living bark ; a depth of substance, which, judging from the experiments 

 previously alluded to, and from the shape and character of the process, the 



