July 28, 1888. 
THE GARDENING WORLD. 
757 
great damage among the Pine plantations. Sometimes 
these insects appear in vast numbers and cause great 
terror among the inhabitants, for when flying they 
hum like a large bee. The Siricidae turn up at times in 
the most unlikely places ; wood brought from abroad, 
and used in dwelling houses, often contains their 
larvae. 
In one instance several specimens of Sirex gigas were 
seen to emerge out of the floor boards in a private 
house (Linncean Transactions, x., 403). Many 
other cases could be quoted of the Siricidae appearing 
in large numbers out of newly timbered houses. So 
hard and strong are the mandibles of these that in¬ 
stances are recorded in the Transactions of the Learned 
Societies of France, that the larvae have bored their 
way into lead to the depth of a quarter of an inch. 
The Entomological Society of France received, in 
1883, a sheet of lead, which once formed the roof of a 
dwelling, completely bored by the Siricidae, whilst 
endeavouring to escape from their imprisonment in the 
wooden beams. 
In the Transactions of the Entomological Society, 
vol. i., there is recorded an instance of a piece of Pine 
wood, about 20 ft. long, so bored by these insects that 
the wood was only fit for burning. This piece was 
placed in an out-house, and about half-a-dozen insects 
came out daily. The females averaged one in twelve 
for the first six weeks, but afterwards became more 
numerous, and continued to make their appearance 
until the end of November. During the last few weeks 
females alone were produced. 
The vast order of Coleoptera possesses numerous 
species of wood-boring insects of all sizes and de¬ 
scriptions inhabiting every quarter of the globe. 
Of the English species, the Stag Beetle (Sucanus 
cervus) is the largest and best known. The larva 
spends four years in the interior of the tree, causing 
great destruction. The beetle may. be seen flying 
about in the evening during the summer months. The 
larva of Crypto hynchus Lapthi, one of our largest 
weevils, is very destructive to the wood of the Willow. 
The Capricorn beetles are nearly all wood-borers. The 
genus Cerambyx, noted for its long antennae, spends 
the larval stage boring away the interior of various 
trees. The Musk Beetle is the commonest, and perhaps 
the most beautiful species of this genus. This beetle 
has a peculiar scent, like that of Boses, it also produces 
a sound, when touched, not unlike the screech of the 
bat. 
Tomicus typographus attacks trees in vast numbers ; 
as many as 50,000 of these beetles have been found in 
one tree. The family Scolytidae contains a vast number 
of beetles, nearly all spending their larval stage in 
boring between the wood and the bark. This causes 
the rain to soak under the bark. Decay sets in, and 
the tree gradually dies away.— E. T. B. 
-- 
HARDY TREES AND SHRUBS IN 
FLOWER. 
The Tulip Tree. 
In many of the southern counties of England, Lirio- 
dendron tulipifera almost attains the dimensions which 
it does in its native habitats in North America. It 
seems to require shelter, however, from other trees to 
develop its noblest proportions, and to be planted in 
deep soil, these conditions being fulfilled in many 
gardens along the valley of the Thames, where it 
delights in the rich alluvial soil of the old river bed. 
In a low-lying part of the grounds at Chiswick House, 
Chiswick, near the pond, we noticed the other day a 
tall straight-trunked tree, about 70 ft. or 80 ft. in 
height, still in full vigour, and covered with its curious 
and beautiful flowers, which are unfortunately too far 
above the eye to be inspected. They have not inaptly 
been compared to those of a Tulip, giving rise to the 
specific and popular name, and are variegated with 
yellow and orange on a greenish ground. They are 
favourites for decorative purposes, and are much used 
in some establishments, in some instances in conjunction 
with white Water Lilies. Although it flowers so 
freely, it does not appear to produce fertile seeds very 
often in this country, though it does so in France. In 
neither case, however, do the seeds vegetate so freely as 
those imported from America. The flowers, like many 
of the Magnolias and Michelias, are agreeably fragrant. 
The foliage alone makes this tree a grand acquisition to 
our lawns and pleasure grounds. 
The Common Lime. 
At the present time the Lime trees are amongst the 
chief ornaments in woods, parks, pleasure grounds, or 
in the suburban streets and squares of London. 
Nowhere do they flower to greater perfection than when 
planted singly or in lines where the sun and air have full 
play amongst the branches. Under these conditions 
none of our native trees produce a greater quantity of 
bloom at this season. The Limes are essentially late- 
flowering trees, and the common species, Tilia vulgaris, 
better known, perhaps, as T. europaea or T. intermedia, 
comes into bloom when T. platopliyllos is about past 
its best. As a town tree it stands the smoke very well, 
but loses its leaves sometimes by the first week in 
September in dry situations, as is very evident in the 
streets of London. It seems to be a favourite with 
many for the purpose of forming a screen between the 
villa gardens and the public highway; but unfortunately, 
although the foliage is good, it seldom flowers in those 
situations, owing to the severe pruning to which it is 
subjected. In the Marquis of Bute’s grounds at Chiswick 
House, are some magnificent specimens of the common 
Lime about 100 ft. high. One of them seems to have 
vied with a giant specimen of the English Elm (Ulmus 
campestris) as to which would overtop the other, but 
still the Lime is the tallest, and is now a picture of 
beauty, laden with its trusses of bracteate flowers. 
The Climbing Hydrangea. 
Botanically this is perhaps best known as Schizo- 
phragma hydrangeoides, less frequently as Hydrangea 
scandens. It is killed during severe winters in some 
situations even when planted on a wall, while in other 
cases it outlives many winters and attains considerable 
size, like a plant on the herbaceous ground wall at Kew, 
with an eastern aspect. This season it has produced 
numerous trusses of its curiously radiant white flowers 
Hollyhock Fungus : Puccinea malvacearum. 
that have lasted many weeks in good condition, 
although now past their best. When in perfection 
they emit a distinct and agreeable though not powerful 
odour, especially in the early morning when moist with 
dew. 
The White-beam leaved Spiraea. 
The size attained by this shrub, and the quantity of 
flowers produced, as well as the lateness of the season 
when it comes into perfection, should be sufficient 
recommendation for a more extended cultivation than 
it enjoys at present. It is the Spiraea discolor ariaefolia 
of botanists, a native of North-west America, and 
extremely hardy, perhaps, in any county of the British 
Islands. In good soil it attains the height of 8 ft. or 
10 ft., producing huge terminal panicles of small white 
flowers that bend down the stems with their weight 
and appear like a white cloud, the individuality of the 
flowers being lost at a short distance off. In poor soil 
or exposed windy localities the stems may not exceed 
4 ft. or 5 ft. The leaves are dark green above, and 
hoary beneath, being in this respect likened to those 
of Pyrus aria (the White-beam). It is now very gay in 
the shrubberies of Devonhurst, Chiswick. 
Douglas’ Spiraea. 
There are several species of Spiraea flowering at pre¬ 
sent, with spicately panicled inflorescences of rose or 
pink flowers ; but the two that are most liable to be 
confused are the subject of this note, S. Douglasii and 
S. tomentosa. The first-mentioned is the tallest, and 
has oblong leaves, serrated towards the apex, and densely 
felted beneath with white tomentum. S. tomentosa 
has ovate leaves, and densely felted beneath, and does 
not exceed 2 ft. or 3 ft. in height, while the other is 
much taller. Both have terminal panicles of rose- 
coloured flowers, and are now in fine condition. 
HOLLYHOCK DISEASE. 
Fortunately for gardeners the virulency of this 
disease has greatly abated or almost died out within 
the last few years, whereas in 1873 and 1874 it threat¬ 
ened almost to exterminate Hollyhocks from gardens. 
The fungus is believed by some to be a native of Chili, 
from whence it was introduced to Britain and Con¬ 
tinental Europe, but however that may be, it certainly 
attacks several other members of the Mallow family, 
including Malva sylvestris, growing in unfrequented 
spots in this country far from any garden from whence 
the spores could be disseminated. It most commonly 
commences the attack on the lower surfaces of the 
leaves, although not strictly confined to them, and in 
its march of progress destroys not only the foliage 
when very virulent, but attacks the green unripe fruit, 
in which it takes up its quarters and gets disseminated 
to the seed bed, and so renews its career on the 
seedlings. Plants affected by it appear covered more 
or less with reddish brown spots, which grow darker 
as they tend towards the hibernating stage. The 
disease is caused by a fungus, the Puccinia malvacearum 
of botanists, and the Puccinia stage in its life cycle is 
the only one at present known to science. Leaves, 
stems, or fruits that are affected by it should be 
completely cut away, and burned as soon as they 
exhibit signs of the mischief. A careful observer can 
easily detect this disease with the naked eye, and 
every care should be taken to effect its destruction. 
-- 
ANTIQUITY OF VEGETATION—IV. 
Cainozoic or Tertiary flora. 
The flora of the Tertiary deposits becomes extremely 
rich in all kinds of vegetation, as it exists at the 
present day in some part of the world or other ; and 
in the lowest strata the remains of plants and animals 
in Britain bespeak a tropical or sub-tropical climate. 
On these grounds it has been reckoned from astro¬ 
nomical calculations that this period commenced about 
2,460,000 or 2,620,000 years ago. In the London Clay 
(Eocene) at Sheppey a most remarkable collection of 
tropical fossil fruits have been found, representing 
Palms and Leguminosae. Many of the Palms appear 
identical with existing species ; while of the Pea family 
about forty distinct kinds have been recognised, allied to 
the Acacias and Mimosa. The London clay was a marine 
deposit brought down by a large river. In the lower 
Bagshot beds of Bournemouth, Palms and Maples have 
been found, as well as Mammoth Trees (Sequoia), 
Eucalyptus, Alder, Plane, Poplar, Elm, Auracaria and 
Ferns. In strata of the same age at Alum Bay Isle of 
Wight, the Pea family is richly represented by Caesal- 
pinias, tall Fig trees, Fig-Sycamores, Aralia and others 
representing types of vegetation now existing in India 
or Australia. The Bovey Tracey beds in Devonshire, 
particularly the brown coal or lignites, are rich in the 
remains of a giant Conifer (Sequoia Coutsiae), like the 
Mammoth Tree of California, also Cinnamons, Ever¬ 
green Oaks, Evergreen Figs, Palms and Laurels. 
Vines festooned the forest trees, while Water Lilies 
floated on the old Lake in which the fossils were 
deposited. 
At the very base of the Tertiary or even in the Upper 
Cretaceous beds of the United States we have evidence 
of a rich flora of an advanced kind, containing Planes, 
some of them with leaves a foot in diameter, Catalpas, 
Horse-Chestnuts, Water-Chestnuts (Trapa), and the 
delicate-leaved Davallia tenuifolia. The latter no 
longer grows in America, but still exists on the 
mountains of Asia, showing that fragile plants may be 
more ancient than the mountains on which they grow. 
Beds of Miocene age in Switzerland, in one locality 
alone, have yielded 900 species, affording abundant 
evidence of an exceedingly rich flora. An important 
and interesting feature of the vegetation of this period 
is the occurrence in abundance of Gamopetalous 
Dicotyledons and of insects in beds on the Bhine. On 
the whole, the flora resembles that now existing in the 
warmer parts of North America and Japan. Beds of 
the same formation in Greenland contain numerous 
plant remains that have been declared identical with 
those cf Central Europe, showing at that time evidence 
of a sub-tropical climate. Besides a host of trees of 
well-known genera, several Gamopetalous Dicotyledons 
occur, such as Viburnum and Andromeda, together 
with the large-flowered Magnolias, giving rise to the 
belief that the plants of this period originated in 
Greenland and migrated southwards through America, 
Asia and Europe. 
In the Pliocene Beds of Europe we have a most 
varied and interesting flora, including Ginkgo, Sedges, 
Sweet Gum (Liquidambar), Bobinia, Honey Locust 
(Liriodendron), Dogwood (Cornus), Myrtles, members 
of the Apple Family, Limes, Magnolias, Oak, and 
Maple, most of which exist in America, Japan, or the 
warmer parts of Europe at the present day.— J. F. 
