EXTRACTS—NATURAL HISTORY. 
515 
these plants, is of no other use than for ornament. The cultivation of Alpine 
plants in pots is so far preferable, as it is then easier to afford them the advan¬ 
tages they have in their wild state. In winter, they may he removed to a cool 
moist place, instead of exposing them to the dry frosts; in summer, they can be 
kept moist, which is the most essential part in the cultivation of Alpine plants. 
—Dr. Link .— Pruss. Gard. Soc., copied from Gard. Mag. 
Ox'alis tetraphy'lla. —This plant is used for ornament, especially for 
edgings. It is also very good when used as sorrel, and the bulbs resemble po¬ 
tatoes in flavour: the leaves, when mixed with New Zealand Spinach, impart to 
it a peculiar and pleasant acid flavour. The plant is very easily cultivated; it 
grows in almost any soil, and increases its bulbs abundantly. If planted in a 
frame, in Spring, it may be obtained earlier.—M. Witzel. — Pruss. Gard. Soc., 
copied from Gard. Mag. 
Culture of Oranges. —M. Mertens et Herrnhausten re-pots his trees every 
sixteen or twenty-four years. The soil consists of two parts cow dung, two parts 
loam, three parts rotten horse dung, and three parts of the old soil from the pots. 
They are occasionally watered, and fresh cow dung is laid on the top of the soil, 
as manure. The trees are pruned in September, in preference to the pruning in 
Spring, by which three or four weeks are lost in their growth.— Ib. 
Alpine Plants. —Dr. Wild describes a method of growing Alpine plants, 
used in his garden at Cassel. On a site of 8000 square feet, he cultivates about 
700 different alpine and forest plants. In five of the beds, a stratum of gravel 
is laid at the bottom, which is covered with peat about 2 feet thick. The rock- 
work is also planted with alpine plants.—I b. 
Passion Flower. —M. "Bosse approves of impregnating with the pollen of 
different species or varieties. In this case, they produce fruit more freely than 
when impregnated with their own pollen. He has, by this cross impregnation, 
originated several varieties.—I b. 
NATURAL HISTORY. 
Ravages of Insects. —No insect makes greater havock of our white thorn 
hedges and apple trees than the little grey moth, Tinea padella, Lin. Wherever 
the caterpillars of this insect seat themselves, they congregate in great numbers: 
every spray is covered. The leaves vanish before them : so that, by midsummer, 
not only single trees, but whole orchards, and entire hedges, from end to end, 
are completely defoliated. Their depredations cease when changed into the 
chrysalis state ; they leave the trees covered with the webs, or rather silken webs, 
by which they transport themselves from place to place; and every leaf is shri¬ 
velled, as if scorched by fire. The familj r of moths are particularly partial in 
their choice of food ; one species affecting only one order of plants. The instinctive 
predelictions of these little creatures have often suggested the idea, that their 
favourite plants might be defended from their visits by the qualities of other 
plants to which they are averse, as a solution of the ivy upon the apple, &.c. 
Whatever quality be hit upon, whether vegetable or mineral, as a safeguard to 
plants, it ought to he administered as an ablution or wash : as such, the garden- 
engine or syringe might be employed with ease, and with little loss of time. 
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