April 4, 1891. 
THE GARDENING WORLD 
491 
ALPINE PLANTS. 
At a meeting of the North of Scotland Horticultural 
Association, held at Aberdeen on the 21st inst, the 
secretary, Mr. Minty, read a paper on this subject, 
contributed by Mr. George Muirhead, Fellow of the 
Botanical Society of Edinburgh, and factor for Lord 
Aberdeen. The revival of the cultivation of hardy 
flowers in our gardens, he said, within the past twenty 
years had done much to increase our knowledge of many 
beautiful and interesting forms of vegetation, and of 
these some of the loveliest were the bright floral gems 
from high altitudes in various parts of the world, 
commonly known as Alpine plants. Alpine plants 
were generally more successfully grown in gardens on 
properly constructed artificial rockwork, but they 
could also be cultivated in pots in cold frames, and the 
more vigorous and hardy varieties were sometimes used 
for the embellishment of the ordinary flower borders, 
their dwarf and spreading habits rendering them well 
suited for this purpose. 
The climate of Aberdeenshire, which was moist and 
cool in summer, appeared to be well fitted for their 
growth, and the abundance of large, weatherbeaten 
stones, which were to be seen lying on the surface of 
the ground in every district of the country, afforded 
every facility for the construction of artificial homes 
for the plants, not to speak of what might easily bo 
made of the innumerable rocky knolls which nature 
has already so freely provided, the beauty of which no 
art of man could equal. It might, therefore, be useful 
to those who propose to try the cultivation of Alpines 
to have some information as to how to make a rockery; 
for upon the proper construction of this, chiefly depended 
the ultimate success of the plants.. In a state of nature, 
generally speaking, their favourites were found growing 
in various positions on the sides of mountains, where 
they had the fullest exposure to light and air 
during the growing season, a deep strong soil, into 
which they could send down their roots, and perfect 
drainage. 
In winter they were covered up with dry frozen 
snow, which preserved them at an equal temperature 
during the stormy season, and with the return of 
spring they awoke from their long sleep with renewed 
health and strength. In summer they were watered at 
the roots by the melting of the snow on the mountain 
tops, and thus never suffered from drought. If they 
could give them all these natural advantages in 
gardens, there was no reason why they should not 
grow as luxuriantly and flower as profusely there as 
they did in their Alpine homes, because, all other con¬ 
ditions being equal, the cultivator would provide 
them with artificial protection from rampant grasses 
and other plants in place of their natural mountainous 
defence against such enemies. 
Of the natural advantages above mentioned, one of 
the most important was perfect drainage, and it was in 
order to secure this, that they cultivated Alpine 
plants on artificial rockwork raised above the ordinary 
level of the surrounding soil. The best and easiest way 
to construct artificial rockwork for people who had only 
ordinary means at their disposal for gardening purposes, 
was to select an open, sunny, well-drained situation, 
free from the shade of trees, and to place on the surface 
of the ground a heap of sandy, strong soil, of the size 
and height of the intended rockery. All over the surface 
of this mound, large weather-beaten stones should be 
sunk to half their depth, leaving the remaining half 
uncovered. 
The stones should be placed at various distances 
.apart to accommodate large and small plants, and 
for the generality of species, the spaces between the 
stones should be filled up to nearly the tops of the 
stones with fine sandy loam, mixed with leaf-soil 
and coarse gravelly sand. Some of the spaces, however, 
should be supplied with a mixture of peat and sand, 
for such as required that; and the whole soil should be 
firmly beaten down and rammed into the interstices 
of the stones. Mr. Muirhead’s paper concluded with a 
list of plants which are easily grown. 
• --- 
INSECTIVOROUS PLANTS. 
The secretary then read a paper by Mr. Robert Lindsay, 
curator of the Royal Botanic Gardens, Edinburgh, on 
insectivorous plants. Insectivorous plants had the 
power of taking solid food into a structure which we were 
justified in calling a stomach. The principal families 
in which there were plants possessing this remarkable 
power were the Nepenthace®, Sarraceniaceae, Droseracese, 
and Urticulariace®. The Nepenthes or Pitcher-plant 
family consisted of over thirty different species, besides 
an increasing number of hybrids. They were half 
shrubby, climbing plants, natives of the hotter parts of 
the Asiatic Archipelago, from Borneo, which was their 
head-quarters, to Ceylon, with a few outlying species 
in New Caledonia, in tropical Australia, and in the 
Seychelle Islands. 
The pitcher, which was its most striking feature, 
was an appendago of the leaf, developed at its apex, 
and furnished with a stalk. In all cases the mouth of 
the pitcher was furnished with a thickened corrugated 
rim which served three purposes—(1) it strengthened 
the mouth and kept it distended ; (2) it secreted 
honey ; and (3) it formed a row of incurved teeth, 
which descended into the pitcher and prevented the 
escape of insects. In the -interior of the pitcher there 
were three principal surfaces—namely, an attractive, a 
conductive, and a secretive or digestive surface. The 
attractive surface was on the under side of the lid of 
the pitcher, and also on the rim. The under side of 
the lid was provided with an abundance of honey- 
secreting glands. This was the bait which was cun¬ 
ningly provided, so that the victim might be led 
pleasantly on its way to destruction. 
The conducting surface extended from the mouth of 
the pitcher down to a variable distance. It was formed 
of a fine network of cells, covered with a glass-like 
cuticle which afforded no foothold to insects. The 
remainder of the pitcher was entirely secretive, and 
consisted of a cellular floor crowded with circular 
glands in very large numbers. These glands secreted 
an acid fluid, which was present in considerable 
quantity before the lid of the pitcher was opened. 
Animal matter put into the pitchers, such as small 
pieces of meat or white of an egg, became acted upon 
in a short time. Large numbers of ants, cockroaches, 
&c., were captured naturally by Nepenthes pitchers. 
The Sarraceniace®, or American Pitcher plants, con¬ 
sisted of six species of Sarracenia, nearly all of which 
had several varieties and a large number of home- 
raised hybrids. 
All the species of Sarracenia were in cultivation, 
were similar in habit, and were natives of North 
America, where they were found growing in bogs, and 
even in places covered with shallow water. Sarracenias 
might be divided into two sections—those having the 
mouths of their pitcher-shaped leaves open in conse¬ 
quence of the lids standing erect, and those having the 
lids projecting over the mouths of the pitchers. The 
structure of the Sarracenia was somewhat similar to 
that of Nepenthes, and the modus opcrandi by which 
insects were “ caught and done for” was also similar. 
The Droserace® or Sun-dew family was widely distri¬ 
buted over the temperate zone. 
The leaves of Drosera were covered with a viscid 
secretion. When a fly alighted on a leaf it was held 
fast. In a short time all the hairs in the immediate 
neighbourhood pointed in the direction of the fly, 
bathing it with acid secretion, which has found to be 
analogous to pepsine. The Lentibularisce® or Butter- 
wort family contained Butter-wort and Bladder-wort ; 
the former captured insects by the upper surface of its 
leaves, which were set with glandular hairs which 
secreted a viscid fluid, while the latter captured 
insects by the small bladders attached to the root-like 
processes. These bladders possess a most ingonious 
trap-door mechanism which only opened inwards, so 
that when a cyclops or other animalcule was once in, 
it must remain there. 
The cultivation of these plants was by no means 
difficult. They required pretty much the same descrip¬ 
tion of soil, moisture, and general treatment. Ne¬ 
penthes alone required much heat; an average tempera¬ 
ture of 70° suited them very well. The soil should 
consist of fibrous peat, with the earthy matter shaken 
out. To this should be added from a third to a half 
of chopped sphagnum, and a sprinkling of charcoal, 
potsherds, and silver sand, thoroughly mixed. Owing 
to the large amount of water required, good drainage 
must also be given. To have abundance of pitchers 
produced they should be constantly cut back, as when 
growing too freely they usually failed to produce 
pitchers. 
The writer preferred, on the whole, seeing Pitcher 
plants grown in baskets, as the pitchers showed in 
them to better advantage. An ordinary stove was 
the best place to grow them. It was gratifying to 
find that the cultivation of such plants was very much 
on the increase, and that the beauty, singularity, and, 
above all, the wonderful adaptation in form which they 
manifested were becoming more appreciated. Hearty 
votes of thanks were given to Mr. Muirhead and Mr. 
Lindsay for their most interesting and instructive 
contributions. 
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- -> - 
A Tuberous.rooted Vine.-—A plant of consider¬ 
able interest is the new tuberous-rooted Vine (Vitis 
Martini, Planch.) from Cochin China. It fruited in 
1888 in Hong Kong for the first time. The seeds were 
procured from the Botanic Gardens, Saigon, in 1883. 
The seedlings were planted out the same summer and 
made several shoots, each of which died down in the 
winter. They began to make fresh shoots about the 
middle of April, 1884, and grew well during the 
summer, but showed no inclination to flower ; and 
again died down in the winter. Last summer they 
started vigorously and showed flower about the end of 
May. Many of the bunches, however, failed to 
develop fruit, owing apparently to imperfect fertilisa¬ 
tion ; but there was a good average crop of bunches on 
the canes irrespective of the failures. The fruit was 
ripe in October, many of the bunches weighing 1 lb. 
each. The berries when ripe are jet-black, and rather 
under the average size of ordinary grapes. The seeds 
are large in proportion to the size of the berry. The 
flavour is a peculiar blending of sweetness and acidity, 
very pleasant, but tending, in my case, to leave a 
curious smarting sensation on the tongue; others 
might not find this peculiarity at all objectionable.— 
Mr. Ford, in the Kew Bulletin. 
Different Plants to which the name Cedar 
is applied.—In this country we apply the name Cedrus 
to that genus only, and speak of the Cedar of Lebanon 
(C. Libani;, the Indian Cedar (C. Deodara), and the 
Mount Atlas Cedar (C. atlantica). But so popular has 
the name become, that many countries have their own 
tree or trees which they call Cedars. Several of these 
are Coniferous trees, as for instance the Red or Virginian 
Cedar (Juniperus virginiana), the Sharp Cedrus (J. 
Oxycedrus), the Barbados Cedar (J. barbadensis), the 
Bermuda Cedar (J. bermudiana), the Japan Cedar 
(Cryptomeria japonica), Cedar of Goa (Cupressus lusi- 
tanica), and the White Cedar (C. thyoides). Trees 
belonging not only to various other genera but to 
different natural orders are called Cedars, amongst 
which may be mentioned the Bastard or Sweet-scented 
Barbados Cedar (Cedrela odorata), the Bastard Cedar 
(Guazuma ulmifolia), the Guiana or White Guiana 
Cedar (Icica altissima), the Honduras Cedar (Cedrela 
odorata), the Cedar of New South Wales (C. australis), 
the Stinking Cedar (Torreya taxifolia), the White Cedar 
of Australia (Melia australis), the Prickly Cedar of 
Victoria and Tasmania (Cyathodes acerosa), a plant 
belonging to the Epacris family, and the White Cedar 
of Dominica (Bignonia Leucoxylon). Thus there are 
eleven distinct genera, and many species belonging to 
several natural orders to which the name Cedar is 
applied in different parts of the world ; and the above 
does not include all the species popularly named Cedars. 
Ozone and Plants. —Ozone is a concentrated form 
of oxygen, and consists of a chemical union of three 
atoms of it. The combination, however, is a very 
unstable one, and the molecule of oxygen is ready to 
break up whenever it comes into contact with organic 
matter with which it unites and alters its constitution. 
For this reason ozone is of immense service in purifying 
the atmosphere and rendering it wholesome for human 
life, as well as animal life of all kinds. It is common 
knowledge that thunder has the effect of purifying the 
atmosphere. This it may do in various ways ; but the 
electric current is a powerful agent in the formation of 
ozone, which in turn renders the hurtful impurities 
innocuous. Now flowering plants, both odorous and 
inodorous have the faculty of generating ozone, but the 
former possess the property in a much greater degree. 
Pine trees generate ozone largely, and it is regrettable 
that Coniferous trees generally refuse to thrive in the 
heart of London and other densely populated cities and 
towns, otherwise we would possess a valuable means of 
purifying the atmosphere by planting the odorous 
kinds largely. We can, however, use odoriferous trees 
and shrubs of various kinds out-of-doors, and other 
subjects indoors. Amongst the subjects that may be 
grown indoors in winter and outside in summer are 
species of Eucalyptus, Myrtles, Boronias, Coleonemas, 
Laurus nobilis, Umbellularia Californica (Oreodaphne) 
Oranges, Pelargoniums, especially the strongly-scented 
kinds, such as P. denticulatum, P. Radula, P. tomen- 
tosum, P. citriodora, and others, as well as an innumer¬ 
able list of odorous plants which may readily suggest 
themselves to the cultivator. 
