Once a Week (magazine)/Series 1/Volume 3/Nepenthes; or, Pitcher-plants
NEPENTHES; OR, PITCHER PLANTS.
The almost endless diversity of form and colour which mark the productions of Nature, so definite in the broad lines which separate the great divisions from each other, so extensively varied within those limits, so often characterised by forms of symmetry and blendings of colour inimitably beautiful, call forth universal admiration, while they invite and reward intelligent research.
This extreme variety in vegetable life constitutes one great charm of foreign travel, while it contributes largely to the ever-fresh and welcome enjoyment of the home garden and the conservatory. This pleasure is every year shared by increasing numbers, and few signs of social progress are more gratifying than the addition of one or both these latter sources of recreation and instruction to nearly all except the lowest class of rural or suburban dwellings.
The relations subsisting between the structure of plants and peculiar conditions of temperature and climate have given to different parts of the world a specific and peculiar vegetation. Formerly, the plants peculiar to each region were known to few beyond the inhabitants of the countries in which they grew; but the pursuits of commerce and science have, in recent years, made the inhabitants of Europe acquainted with the production of all other countries; and the increased attention to horticulture in our own country, especially the labours of the Horticultural Society, have encouraged and rewarded the introduction and culture of whatever rare, curious, or beautiful forms of vegetable life have been found in any part of the globe.
Among plants of the latter class few are more remarkable and striking than the Nepenthes, or Pitcher-plants. One variety of this remarkable plant, Nepenthes distillatoria, was introduced to England towards the close of the last century from China, and hence for a long time was designated the Chinese Pitcher-plant. In recent years this, and other species belonging to the same genus, have been found in countries at a remote distance from China. Mr. Ellis saw the kind first brought into England growing, apparently in a wild state, in Madagascar; other species have been discovered in Bengal and Ceylon, and a considerable number in the large and but partially explored island of Borneo.
All the plants of this genus are natives of the tropics: but two other genera of plants, the Sarracenia and Cephalotus, greatly resembling the Nepenthes in organic structure, and exhibiting also in a modified form the Pitcher, or Ascidium, are natives of more temperate parts. The former, which is sometimes called the Side-saddle Plant, having been found in the United States, and the latter (which is an exceedingly curious and beautiful plant, one of the varieties being ornamented with stripes of red or purple) is a native of New Holland, and is sometimes called the Australian Pitcher-plant.
The habit of growth and mode of culture are the same for the several species of Nepenthes. All are ever-green creepers, and in their native countries climb upon the trunks of trees to the height of thirty feet. The glass-houses in which they are grown in England seldom allow them to rise more than six or seven feet above the pot in which they are planted, and only a few attain even that elevation. The long slender stems are generally trained round a number of rods, or a wire frame. They grow best in a very moist atmosphere, seldom lower than 60°, having the pots embedded in moss, heated by artificial means to a somewhat higher temperature than the atmosphere. The roots are fibrous, and the stalk, which is smaller than an ordinary quill, is during the first year green, but afterwards turns brown, and is sometimes more than half an inch in diameter. The raceme of flowers is large, but the single flowers are small, dull coloured, and unattractive. The seeds are abundant, and the plant is propagated by seed or cuttings. The climbing habits, and the long, linear or oblong, and dark green shining leaves render the several kinds of Nepenthes highly ornamental; but the curiously constructed and gracefully formed pitcher which hangs by a long slender stalk to the end of each leaf places them among the most singular and attractive objects contained in our houses of glass.
This elegant and unique appendage to the leaves of the Nepenthes, combining lines of graceful curve and forms of exquisite symmetry that might almost have fitted them to be models for the vases or other fictile wares of antiquity, appears to be produced by a series of successive developments in the foliage of this remarkable genus. The leaf, as it first unfolds, presents to the ordinary observer scarcely any sign of the pitcher, except a curious tendril or cirrhus extending beyond the extreme point of the leaf. As this tendril lengthens, the small enlargement at the end increases, and the tendril in the meantime gradually bends upwards at the point like a hook; the part thus bent continues to enlarge, the substance of the stalk appearing to swell, until it attains the size and form of the pitcher. The lid then separates from the rim, excepting at the upper and outer side, where it remains more or less raised, and united as by a hinge to the pitcher. This pitcher, being attached at its base to the slender, tendril-like stalk, hangs suspended six inches or a foot from the point of the leaf with which it is connected. Forty or more pitchers sometimes hang around a single plant. In some species this order of successive development is not followed. In the early growth of some seedling plants examined by Dr. Hooker, and described in a memoir on the origin and development of the pitchers of Nepenthes, recently published in the “Transactions of the Linnæan Society,” he found that the earliest leaves of the seedling plant became perfect pitchers, joined by the stalk or petiole to the stem, as in Sarracenia, without any intervening leaf or tendril.
Singular as is the structure, and elaborate as appears the organisation, of these slight delicately-formed pitchers, and striking as is their resemblance in structure and in form to some of the most useful productions of human skill, another circumstance, in some respects yet more remarkable, remains to be noticed. As the pitcher swells, and while the aperture remains hermetically closed by its lid, a quantity of pure, tasteless, and colourless water collects in all the species in the cavity of the pitcher, which, when the lid rises, is generally found to be at least one-third full of this infiltrated fluid.
To whatever change this water may be subjected in plants growing in a natural state, it does not appear that, under the culture to which they are subject here, the quantity ever increases after the operculum or lid is raised; on the contrary, although the plant requires to be kept in a moist atmosphere, the water in the pitcher diminishes and gradually dries up. Such a remarkable arrangement is doubtless intended to answer an important purpose. Some have supposed that the inner surface of the pitchers is lined with minute rootlets, which draw nutriment from this natural reservoir; but botanists have failed to discover them. The plant does not seem to be at all dependent on this water for vigorous and healthy growth, as it is often robust and luxuriant when there are few if any pitchers.
The greatest practical utility of the pitchers hitherto discovered has been the slight check they furnish to the increase of insect life. The inner edge of the annulus of the pitcher is fringed with stiff hairs growing in an oblique, descending direction, along which insects easily pass to the water, but through which few of them seem able to make their way back; and in most of the pitchers a short time after the lids have been raised a number of insects are found drowned in the water. Hence a healthy pitcher-plant is considered useful in a house containing orchids or other tender plants, as cockroaches and such destructive insects are not unfrequently found dead in the pitchers, to which they have been attracted by the water, or by a sugary secretion said to be found in the inside of some species; while the young succulent roots and flower-buds of the orchids around have been left uninjured.
The accompanying woodcut exhibits three of the species in most general cultivation. The central plant is the Nepenthes Rafflesiana, so called in honour of the late Sir Stamford Raffles, Governor of Bencoolen, producing the largest and most beautiful pitchers yet grown in Europe. The linear-acuminate leaves are sometimes a foot and a half long. The cirrhus, or stalk of the pitchers, is of equal length. The somewhat pear-shaped pitcher is six inches deep, and two or three inches in diameter towards the base. The lid is an inch and a half in length and an inch wide. The edge of the aperture is ornamented and protected by a broad rim or annulus of a reddish brown or purple colour. The whole of the outside of the pitcher and lid is spotted or blotched with a rich brownish red or purple. A healthy Nepenthes Rafflesiana, with its luxuriant dark green shining leaves, graceful habit of growth, and large richly-coloured pitchers, is an attractive and remarkable object in any collection of plants.
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The plant on the left in the plate is Nepenthes distillatoria, the first species introduced to Europe. The length of its pitcher is equal to those of Rafflesiana, but it is much less capacious. The neck and upper part are exceedingly graceful and almost classical in form. The aperture and lid are circular, and about an inch in diameter. The colour is a rich yellow, shading into red in the upper parts. The attractiveness of this species is increased by the tendency of the cirrhus to curve and form one or two rings, as is often seen in the tendrils of the vine.
The plant on the right is Nepenthes lævis, a less robust but graceful plant with smaller pitchers, presenting in form a medium between the two already described. There are several other species in cultivation, some more rare, but none intrinsically better than those here specified. Dried specimens, however, of several species have been received by Messrs. Low of Clapton, and Veitch of Chelsea, from the mountains of Borneo, far surpassing in size and novelty of form anything previously imagined in connection with this interesting class of plants. Dr. Hooker, who has recently published a very interesting description of them in the “Transactions of the Linnean Society,” mentions one as “a noble species, with very remarkable pitchers, very unlike any other species;” and describes another as “certainly one of the most striking vegetable productions hitherto discovered.” We are not surprised at this designation of a plant producing pitchers six inches in diameter, and twelve inches long, the aperture of which is covered with an everted annulus or ring an inch or an inch and a half broad. We can only hope that seeds have come, or will follow the dried specimens, so that these magnificent species may be added to those we already possess.
Mr. Veitch of the Exotic Nursery, Chelsea, amongst the most successful cultivators of these curious plants, and to the 314,000 visitors who annually resort to the Royal Gardens at Kew, the pitcher-plants are always attractive objects.
E. W.