LIII. — THE MISTLETOE. 
Viscum album Linne. 
P ARASITISM is generally accompanied by considerable structural degeneracy. 
It is difficult, therefore, in an Order such as the Santalales, the members of 
which are mostly parasites, to decide which characters are the results of such 
degeneracy and which may be evidences of primitive grade. There are, however, 
few characters common to all the six Families comprised in the Order. The parts of 
the flower are in whorls, the perianth generally of one whorl only and superior, the 
stamens superposed upon the perianth-leaves, and the carpels, one to three in number, 
syncarpous, inferior, and with one ovule in each. 
Two Families are each represented by a single British species, the Loranthacea; 
and the Santalace <e. 
The Loranthacea comprise upwards of five hundred species in more than twenty 
genera ; but the great majority of them are Tropical. Such heterophytic modes of 
life as climbing, epiphytism, and parasitism are all more frequent in the acute 
struggle for existence that characterises the dense vegetation of those latitudes. 
Most of the Family are evergreen shrubs, attached to the branches of their host- 
plants by means of suckers or haustoria , which seem to be structures of a very 
special character, though they have often been regarded merely as modified adventi- 
tious roots. As the leaves are green, these plants are not wholly parasitic, but 
probably depend upon the host-plant mainly for the water and dissolved saline 
substances that plants of normal nutrition ( autophytes ) obtain by their roots. The 
perianth consists only of a calyx, which is superior where an ovary is present, its 
sepals being valvate in the bud, touching, that is, without overlapping. The ovary 
is one-chambered and contains one erect seed with abundant fleshy albumen, and not 
infrequently more than one embryo. The thick radicle, or rudimentary tap-root, 
points towards the apex of the seed ; and the two cotyledons are blunt and fleshy. 
The genus Viscum derives its name, which is used by Pliny, from the Greek 
/£os, ixos , or /^icr/co?, biskos, which apply also to the bird-lime prepared from it. 
It forms no cork, but the epidermis of the stem persists and grows so as to 
accommodate itself to the increasing girth ; thus the stem remains smooth and green. 
Each bifurcation of these yellowish-green stems represents a year’s growth. 
The small, green, inconspicuous flowers are dioecious, being generally grouped 
in sessile cymose clusters of three at the apex of each branch ; and there is a slight 
difference in the shape of the blunt, 5 — 7-veined leaves in the two sexes, those on 
the male being slightly narrower. The flowers open from March to May and 
contain some honey, for the sake of which they are visited by flies and bees. There 
are four sepals, and in the male flowers the anthers adhere to them, and each has 
numerous pollen-sacs opening by separate minute pores to discharge the pollen, so 
that the surface of the anther resembles a honey-comb. 
