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pyramid orchis


Значение термина pyramid orchis в knolik


pyramid orchis - PYRAMID ORCHIS (Orchis pyramidalis)
pyramid orchis - There are all sorts in the plant world, and the Pyramid Orchis is prince of mechanicians there. "In no other plant, or indeed in hardly any other animal, can adaptations of one part to another and of the whole to other organisms widely remote in the scale of Nature be named more perfect than those presented by this orchis." This was the final judgment of Charles Darwin as he finished a most careful study of the plant. And since the colleagues it has chosen in the animal world to work out its plans are the butterflies by day and the moths by night, whose touch is as gossamer and whose probosces are of infinite delicacy, it stands to reason that its elaborate mechanism must be of the finest possible order. Bees that are favoured by many a delicate flower seem coarse and clumsy when the Pyramid Orchis is in question. That the plant is very beautiful our illustration well shows. "I know of no more beautiful sight in the floral line than to see a gently undulating grassy hillside decked and furnished with the rich rose-coloured flowers of the orchis in question, and interspersed at irregular intervals with patches of the deep-blue flowers of the devil's bit," says one writer (Webster, "British Orchids."). The leaves are the palest green and unspotted, and their long, lance-shaped blades make a lovely contrast to the vivid blossoms. When the spikes of rose-red flowers first open, each is a perfect pyramid, rather short, with a broad base. Fully opened flowers are round the bottom and, tapering upwards, are all stages of flowers to the youngest buds at the top, and all are rose-red, for the bracts that wrap up the actual rose-red petals in the buds are themselves warm-tinted. This pyramid formation at once declares this orchid, and hence its name. Later, however, when the top buds open and the spike lengthens, something of this characteristic shape is lost.

It seems rather a reflection upon our boasted modern catholicity in garden matters that this plant, albeit wild, is not more frequently cultivated in our gardens. It is easy to grow if it be given a somewhat chalky soil and a fairly open situation. It multiplies quickly, and gives brilliant touches of colour in June, July, and even August. Moreover, it is a joy for the purpose of gathering, for the spikes will deck a room a fortnight or more if they are put into water with a piece of charcoal to keep it sweet. Very occasionally a plant will be found which bears white flowers.

Passing from the beauty of its outward semblance, let us go on to discover why it deserves Darwin's encomium. Of course, it is to the flowers that he specially alludes, and since they are so distinguished it is worth a little pains to understand them and a lens to read them with greater distinctness. There are three narrow, spreading, coloured sepals outside, then three red petals - two small and standing up to form a hood over the centre of the flower, and one very large in proportion hanging down. This large one is divided into three lobes, and is known as the "lip," or "labellum." On this lip are two strongly marked ridges which, widely apart at the middle of the lip, converge into the centre, so that anything passing between them is led straight into the very heart of the flower. The back part of the labellum is fashioned into a very long spur or pocket. Now, take a lens and look into the centre of the blossom. Under the petal hood is a short, thick column which represents the filament of the one stamen and the column from the ovary joined together. The hinder part of this carries the two-celled anther, and in each of its cells is a pear-shaped mass of pollen grains all united by thin elastic strands. Each mass is known as a "pollinium," and it boasts of a slender stalk which is set in a sticky disk. The two disks are joined together to form a saddle-shaped object, which is enclosed in an envelope called the "rostellum." We shall see later that this is veritably a saddle, and that the pollinia are the riders that use it. This rostellum overhangs the forepart of the column, which divides into two rose-red sticky stigmas or receptive organs. When the flower opens, the rostellum is always ruptured by some means or another, and hangs a little below the saddle, partly closing the mouth of the ovary - "Like a trap placed in the run for game," says Darwin. The slightest touch, even a hair pushed at it, is sufficient to depress it. The ovary is very long and narrow, and has a curious twist in it. It contains very many minute seeds. Now, watch a butterfly hover over a flower just opened; it settles on the three-lobed lip, and pushes its thin and most delicate proboscis between the ridges, and so into the flower. The opening is so fine that the insect will almost certainly touch the rostellum and depress it, and so necessarily leave bare the saddle above. Directly the air touches the moist under-surface of the saddle, its two flaps suddenly begin to curl and firmly clasp the proboscis - the saddle is being harnessed to the steed. The "glue" on its under-surface sets rapidly, and in a moment or two the pollinia, always attached to the saddle, are drawn from their niche under the hood, and are riding on the proboscis. Meanwhile, the butterfly is exploring the long pocket. Now, it is a very strange thing that no single drop of honey has ever been found in this apparent honey-sac, hence this orchis has been called a "Sham Honey Flower," and the taunt has been thrown that it is merely a clever deceiver who deludes generation after generation of insects. But this is unjust, for though there is no honey, so to speak, loose in the pocket, yet in the tissues under the skin are copious sweet juices, so copious that they ooze out in drops if the end be cut off. Therefore, Darwin came to the conclusion that butterflies and moths actually pierce the skin and suck the juice out of the tissues. Perhaps the little extra time this takes is the very time that the pollinia need to get safely mounted on their saddles.

Finally, the insect backs out and flutters gaily away, carrying the twin riders. At first they are erect enough, but within half a minute they have fallen slightly away from one another. Over another flower hovers the butterfly; in it plunges, and as it does so the two pollinia-riders strike on the sticky surfaces of the two stigmas, for the exact angle at which they fell apart is the exact position that will cause them to do this. The stickiness is sufficient to drag some of the pollen grains out of them, tearing their elastic threads, and these fertilise the stigma. The rest of the pollinia ride off again. But the proboscis of the insect has now an additional pair of riders - the pollinia from the flower it has just visited. Like a circus horse collecting riders, so the butterfly or moth, as the case may be, may collect pair after pair of pollinia on its proboscis. Thus one poor individual (a Caradrina) was found to be carrying no fewer than eleven pairs, one behind the other, some full of pollen grains, others nearly emptied by the successive stigmas it had visited during its journeyings.

No fewer than twenty-three kinds of moths and butterflies have been caught visiting this orchid. It is easy to know where they have been from the tell-tale and characteristic pollinia they carry. It is wholly dependent upon them, as we have seen, for the carriage of its pollen from flower to flower, and how well they co-operate was pointed out by Darwin, who counted forty-eight out of forty-nine flowers on a single spike that had been visited. "These facts," he said, " show how well moths and butterflies perform their office of marriage priests." And the result of their kind offices is the production of vast quantities of most minute seeds. Happily they do not all become parents themselves; if they did the offspring of a single plant would, in four generations, completely cover the world! In the Orchid, as in many other plants, is exemplified something of Nature's reckless extravagance.

The scent of this plant seems to vary. It is usually called sweet-scented, but at night may have a foxy odour (supposed specially to attract moths, as its purple colour renders it almost invisible). At other times it seems almost scentless. It may be found in flower from June to August.

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