Deg 22, 1882.] 



• KNOWLEDGE 



477 



A NATURALIST'S YEAR. 



By Grant Allex. 

 III.— THE MISLETOE BOUGH. 



OF course, everybody has a Lit of misletoe in Iiis house 

 just at the present moment; and therefore I feel 

 sure I could Iiave no better text in tlie world on which to 

 preach my Christmas sermon than its forked branches and 

 its semi-transparent white berries. So I stick a spray of 

 the uncanny green thing in the little red Japanese vase 

 before my eyes as I write, and I strongly advise you to do 

 the same, as a sort of check or reference, while you follow 

 my didactic exposition. Misletoe, we all know, is a para- 

 site ; and yet there are many worse parasites in the world 

 than that pretty green-leaved plant, with its strange angular 

 forks and its graceful bunch of pale white fruitlets ; for 

 you observe at once that it has foliage of its own. Xow, 

 regular thorough-going parasites, such as broomrapes and 

 dodder, have either no leaves at all, or else have 

 them reduced to mere functionless scales upon the 

 tall, naked flower-stem. Naturally, as soon as a plant 

 has begun to live entirely upon organised material 

 stolen from other and more industrious accumula- 

 tors, it has no further need for leaves of its own. 

 Misletoe, however, though a very old parasite (as shown 

 by the fact that it belongs to a numerous parasitic 

 family, rich in species, especially in the tropics) has never 

 acquired such habits of complete sponging as these very 

 degraded leafless plants. It has a little honesty left in it 

 still. Yet if you read any of the old-fashioned books about 

 botany, you will be told that misletoe is a complete 

 parasite, while dodder is an incomplete one. The phrase 

 and the distinction which it implies have descended to us 

 from times when vegetal physiology was less understood 

 than at the present day ; but people go on using them still 

 in a somewhat unthinking fashion, though the progress of 

 knowledge has exactly reversed our ideas as to the true 

 state of the case. Let us look a little at the origin and 

 functions of the misletoe, and we shall then see how far 

 it has really become degraded to parasitical habits. 



I don't know whether you will be able to find a single 

 belated flower upon your misletoe bough, though I am 

 afraid there isn't much chance so late in the season as this ; 

 for the plant generally blossoms early in the year. But 

 whenever you do come across one in flower, you will find 

 that it points back to an ancestor not unlike the common 

 dogwood. The little blossoms are stuck close in the angles 

 of the branches, where they fork, and they are of two 

 kinds, male and female, each growing on a separate plant. 

 The male flowers consist of a very small calyx, enclosing 

 four minute petals, with a stamen fastened on to the middle 

 of each in a very close fashion ; and they grow in little 

 groups of four or five together, surrounded by a cup-shaped 

 bract The female flowers, again, consist of a calyx which 

 has grown into one piece with the berry, and of four ex- 

 tremely tiny petals. Like the males, they arc surrounded 

 by a bract, but they generally grow solitary within it, or 

 at most, by twos and threes. All these peculiarities 

 show that the misletoes are a very ancient, though much 

 degraded, type — that they have long been started on a 

 special course of development apart from their nearest 

 relatives ; and this is still better seen in some of their 

 tropical congeners, which have the stamens reduced to two 

 or one, and the petals entirely wanting. But the indica- 

 tions thoy give us are clearly these — that the misletoe 

 group are immediately descended from ancestors with a 

 four-lobed calyx, four petals united into a single corolla, 

 four stamens, and an ovary combined with the calyx. All 



the other special marks of the genus — its separate sexes, its 

 stalkless stamens, its inconspicuous calyx, its peculiar mode 

 of fertilisation — have been acquired at a later date than the 

 beginning of its parasitic habit. 



The hypothetical ancestor of the misletoe tribe, then, 

 must have been a free bush or shrub, growing in tlie soil on 

 its own account, and ^ery much like cornel or dogwood. At 

 the same time it must have closely resembled the sandal- 

 wood family, of which we have one rare English example, 

 the small white bastard toadflax which grows among the 

 chalky pastures of our southern counties. Only, the 

 sandalwoods have entirely lost their petals, while many of 

 the misletoe group still retain them. In other respects, 

 however, the sandalwoods have varied less from the primi- 

 tive type than the misletoes. At the same time, it is an 

 interesting fact that several of them have also acquired 

 semi-parasitic habits, as is the case with our own little 

 bastard toadflax, which fastens itself by little suckers on 

 to the roots of other plants, and derives nourishment from 

 the sap in their tissues. This would seem to show that a 

 parasitic tendency existed in the common ancestor of 

 sandalwoods and misletoes even before they began to split 

 up into two groups in diflerent directions. 



The misletoes, however, struck out a new line for them- 

 selves ; instead of merely fastening themselves on to the 

 roots of other plants, they took to an aerial existence upon 

 their trunks and branches. For this role, their peculiar 

 fruit specially adapted them. The bastard toadflaxes 

 bear small one-seeded nuts, adapted only for falling out 

 upon the ground, and, therefore, ill fitted for such a life as 

 that to which the true misletoes have accommodated them- 

 selves. A plant so circumstanced, with a parasitical 

 tendency already ingrained in it, can only fix upon its 

 destined host by means of root-suckers. But the misletoe 

 tribe bears one-seeded coloured berries, instead of green 

 nuts ; and this habit, which is probably of great antiquity 

 in the family, since it is common to all its members, has 

 made an aerial existence peculiarly easy for them to follow. 

 Birds naturally eat the berries, and thus carry them from 

 tree to tree, dispersing the seeds with their droppings on 

 the branches, where the future plant is to gain its dis- 

 honest livelihood. In our own English misletoe, and in 

 most others, the pulp of the berry is very glutinous 

 indeed, being in fact the stufl' employed in making 

 bird-lime; and from its Latin name rise lan -vce even get 

 our English adjective "viscid." Now, this viscidity clearly 

 helps the plant in accomplishing its felonious purpose, for 

 it ensures the seed sticking wherever it may be dropped ; 

 and, in all probability, the berries are often carried clinging 

 to the legs or wings of birds, and then rubbed ofi" at the 

 exact place where the young plants grow best, in the 

 angles of the branches. It is significant, too, that our 

 own kind at least is found most frei[uently on trees which 

 bear fruits or berries, and especially on tlie apple, which 

 are just the ones frequented by frugivorous birds ; while 

 conversely, it is extremely seldom found on nut trees, 

 such as the oak, its rarity in these situations being tlie 

 very thing which gave an oak misletoe special sanctity in 

 the eyes of the Druids (if, indeed, we know anything at 

 all about them). Yet so little does the world at large 

 discover about nature at first hand that I don't doubt 

 ninety-nine people out of a hundred in England still 

 firmly believe that misletoe grows exclusively on oak trees. 



When the little hard seed, surrounded by its glutinous 

 pulp, has thus gummed itself firmly on to the bark of the 

 apple bough, it begins to sprout vigorously on its own 

 account, and to fasten its blunt root on to the tissues of its 

 host. However it may liappen to be stuck on, tlie radicle 

 or sprouting rootlet bends downward or outward towards 



