614 
THE PRINCIPLES OP BOTANY. 
pure water, but Dr.Voelcker lias shown that it contains some 
very important salts. The following are his results : 
Composition of the fluid in the Ascidia of Nepenthes. 
“ Organic matter, chiefly malic, and a little citric acid; 
chloride of potassium; soda ; lime ; magnesia.” 
Prof. Lindley tells us that “ the water contained in an 
unopened pitcher of a plant which flowered in the Botanic 
Garden of Edinburgh was found by Dr. Turner to emit, while 
boiling, an odour like baked apples, from containing a trace 
of vegetable matter, and to yield minute crystals of super¬ 
oxalate of potash on being slowly evaporated to dryness.” 
Besides the N. destillatoria there are about thirty other 
species. They are not remarkable for any particular pro¬ 
perty, and the great interest with which they are viewed, on 
account of their peculiar structure, forms the sole attractive 
feature connected with them. 
Quernales. — Quernal Alliance consists of a large group 
of very magnificent plants, the types of which may be recog¬ 
nised in the Walnut and the Oak. 
The alliance is remarkable for containing only two natural 
orders, and these again possess but few genera, but at the 
same time the species are very numerous, and specific dif¬ 
ferences are in this tribe of unusual importance. Thus, for 
example, some species of oak are highly valuable for use as 
timber, whilst others are comparatively useless. The fruits, 
and even the galls of certain species, are of value, while those 
of others are of little, if any, service. 
The Quernales are described as Diclinous Exogens, with 
amentaceous monochlamydeous flowers, an inferior fruit, and 
an amygdaloid embryo without albumen. 
The natural orders are distinguished as follows: 
1. Juglandaceje. — Ovary \-celled , ovule solitary , erect. 
2. CoRYLACEiE. —Ovary 2 or more , celled ovules pendu¬ 
lous or peltate. 
1. The typical tree of this order, Juglans regia. The 
common walnut is too well known to need scientific descrip¬ 
tion. It is a tree of large size, and though of only a com¬ 
paratively recent introduction to this country, we can boast 
some noble sized trees; and the walnut and hickory trees of 
North America are both striking and valuable. 
Of the former, Beck describes two, and of the latter six, 
species from North America, belonging to the genera Juglans 
and Cary a. We would now speak more particularly of the 
