64 
DEPARTMENT OF BOTANY. 
[upper 
and of a large branch of a Cedar-Tree planted by Sir Hans Sloane, 
in the Garden of the Society of Apothecaries at Chelsea in the year 
1683, and cut down a few years ago, exhibiting 153 concentric annual 
rincrs. 
There are also specimens of the wood and bark, leaves and fruit, of 
Sequoia gigantea, the Wellingtonia or Mammoth Tree of California, 
which grows to the height of 300 or 400 feet, with a circumference 
at the base sometimes amounting to 100 feet, or even more ; parts of 
beams of the Cedar of Lebanon, Finns Cedrus, from the ruins of the 
Palace of Nimroud, where it was found by Mr. Layard ; a branch and 
fruit of Widdringtonia Wallichii, from the Cedarberg, Cape of Good 
Hope ; cones of Dammara australis, D. alba, D. vitiensis ; a section 
of the wood of Dammara australis ; and numerous specimens of 
cones, chiefly from the East Indies and California. Additional speci- 
mens of cones and woods are placed in the Table Cases opposite. 
Specimens of Angiospermous Dicotyledons occupy the remaining 
Cases on this side of the room. 
Case 19 contains specimens of Parasitic Flowering Plants, which 
not only grow upon other plants, but live upon them and obtain 
nourishment from their tissues. These plants present considerable 
modifications of the ordinary type of phanerogams, mostly referable 
to reduction of the nutritive organs. The root cannot be said to be 
present in any, the connection with the nurse-plant being effected by 
apposition of its cells with those of the parasite. The stem may be 
altogether absent or may be represented by a short axis with a few 
brown or coloured scales, or by a creeping rhizome ; leaves and green 
colouring matter {chlorophyll) are entirely absent. There is, however, 
a group of true parasites which possess green leaves or green stems, 
of which the mistletoe is a familiar example. Parasites must not be 
confounded with Epiphytes, such as many Orchids, Bromelias, and 
other so-called "Air-plants," which, though they have no connectian 
with the soil, do not draw their nourishment from the plants upon 
which they grow; nor with climbing plants like the Ivy, which has its 
true root in the ground, and only uses tlie small rootlets on its stem 
as holdfasts. There are, however, many instances of partial parasitism 
and of a parasitic condition being assumed for a part only of the life 
of a plant. The plants exhibited belong to many different natural 
orders, for parasitic habits are found in species with very different 
floral structure upon which their systematic position depends. There 
are, however, very few known cases of parasitism among Monocoty- 
ledons. 
The Walls of the Case are occupied by an instructive series of 
specimens presented by the Rev. R. Blight, illustrating the parasitism 
of the Mistletoe {Viscum album) on the following trees. Acacia, 
Ash, Poplar, Whitethorn, Apple, Maple, Lime, Willow and Oak : 
it is known to grow on more than fifty different kinds of trees, but 
very rarely on the oak, only fourteen cases of its growth on this tree 
Uiing at present known in England. The specimen on the right- 
liand side exhibits well the conical processes of the Mistletoe wood 
