In a moment the onslaught is consummated, and in the struggle which ensues the black a.s.sailant relieves his victim--of his watch presumably, for he has captured the entire garment, which he soon rifles and discards with some show of satisfaction.
And so my carnival proceeds. So it began with the dawn; so it will continue till dusk; and through the night, with new revels, for aught I know, and will be prolonged for days or weeks.
Reflective reader, how often, as you have strolled through some nook in the suburban wood, have you paused in philosophic mood at the motley relics of good cheer which sophisticated the retreat, so pathetically eloquent of pristine joys to which you had been a stranger? Here in my present picnic is the suggestive parallel, for even though no such actual episodes as those I have described had been witnessed by me, an examination of the premises beneath my bramble were a sufficient commentary. These were the unimpeachable witnesses of the pleasures which I have pictured. Dismembered b.u.t.terfly wings strewed the gra.s.sy jungle, among which were a fair sprinkling from that black and white halo already noted. Occasional dead wasps and detached members of wasp and hornet anatomy were frequent, while the blue glitter of the bodies of flies lit up a shadowy recess here and there, showing that Musca had not always so correctly gauged his comparative wing resources as my observation had indicated.
It was interesting to discover, too, down deep among the herbage, another suggestive fact in the presence of a shrewd spider that showed a keen eye to the main chance, and had spread his gossamer catch-all beneath the bramble. It was all grist into his mill, and no doubt his charnel-house at the base of his silken tunnel could have borne eloquent testimony alike to his wise sagacity and his epicurean luxury.
I have pictured my picnic, and the question naturally arises, what was it all about--what the occasion for this celebration? There was certainly no distinct visible cause for the social gathering upon this particular bramble-bush. There were a number of other bramble-bushes in the near neighborhood which, it would seem, should possess equal attractions, but which were ignored. In what respect did the one selected differ from the others?
This bramble had become the scene of my carnival simply because it chanced to be directly beneath an overhanging branch of pine some twenty feet above. Here dwelt mine host who had issued the invitations and spread the feast, the limb for about a foot s.p.a.ce being surrounded by a colony of aphides, or plant-lice, from whose distilling pipes the rain of sweet honey-dew had fallen ceaselessly upon the leaves below. The flies, b.u.t.terflies, and ants had been attracted, as always, by its sweets; the preoccupied convivial flies, in turn, were a tempting bait for the wasps and hornets, and my dragon-fly and mock b.u.mblebee found a similar attraction in the neighborhood.
An examination of the trunk of the pine showed the inevitable double procession of ants, both up and down the tree, with the habitual interchange of comment; and could we but have obtained a closer glimpse of the pine branch above, we might certainly have observed the queer spectacle of the small army of ants interspersed everywhere among the swarm of aphides. Not in antagonism; indeed, quite the reverse; herders, in truth, jealously guarding their feeding flock, creeping among them with careful tread, caressing them with their antennae while they sipped at the honeyed pipes everywhere upraised in most expressive and harmonious welcome.
This intimate and friendly a.s.sociation of the ants and aphides has been the subject of much interesting scientific investigation and surprising discovery. Huber and Lubbock have given to the world many startling facts, the significance of which may be gathered from the one statement that certain species of ants carry their devotion so far as literally to cultivate the aphides, carrying them bodily into their tunnels, where they are placed in underground pens, reared and fed and utilized in a manner which might well serve as a pattern for the modern dairy farm.
Indeed, after all that we have already seen upon a single bramble-bush, would it be taking too much license with fact to add one more pictorial chronicle--an exhilarated and promiscuous group of b.u.t.terflies, ants, hornets, wasps, and flies uniting in "a health to the jolly aphis"?
[Ill.u.s.tration]
_A FEW NATIVE ORCHIDS AND THEIR INSECT SPONSORS_
[Ill.u.s.tration]
In a previous article I discussed the general subject of the fertilization of flowers, briefly outlining the several historical and chronological steps which ultimately led to Darwin"s triumphant revelation of the divine plan of "cross-fertilization" as the mystery which had so long been hidden beneath the forms and faces of the flowers.
In the same paper I presented many ill.u.s.trative examples among our common wild flowers possessing marvellous evolved devices, mechanisms, and peculiarities of form by which this necessary cross-fertilization was a.s.sured.
Prior to Darwin"s time the flower was a voice in the wilderness, heard only in faintest whispers, and by the few. But since his day they have bloomed with fresher color and more convincing perfume. Science brought us their message. Demoralizing as it certainly was to humanity"s past ideals, philosophic, theologic, and poetic, it bore the spirit of absolute conviction, and must be heard.
What a contrast this winged botany of to-day to that of a hundred years ago! The flower now no longer the mere non-committal, structural, botanical specimen. No longer the example of mere arbitrary, independent creation, reverently and solely referred to the orthodox "delight of man." The blossom whose unhappy fate was bemoaned by the poet because, forsooth, it must needs "blush unseen," or "waste its sweetness on the desert air," is found alone in that musty _hortus siccus_ of a blind and deluded past. From the status of mere arbitrary creation, however "beautiful," "curious," "eccentric," hitherto accepted alone on faith--"it is thus because it is created thus: what need to ask the reason why?"--it has become a part of our inspiring heritage, a reasonable, logical, comprehensible _result_, a manifestation of a beautiful divine scheme, and is thus an ever-present witness and prophet of divine care and supervision.
The flower of to-day! What an inspiration to our reverential study! What a new revelation is borne upon its perfume! Its forms and hues, what invitations to our devotion! This spot upon the petal; this peculiar quality of perfume or odor; this fringe within the throat; this curving stamen; this slender tube! What a catechism to one who knows that each and all represent an affinity to some insect, towards whose vital companionship the flower has been adapting itself through the ages, looking to its own more certain perpetuation!
The great Linnaeus would doubtless have claimed to "know" the "orchid,"
which perhaps he named. Indeed, did he not "know" it to the core of its physical, if not of its physiological, being? But could he have solved the riddle of the orchid"s persistent refusal to set a pod in the conservatory? Could he have divined why the orchid blossom continues in bloom for weeks and weeks in this artificial glazed tropic--perhaps weeks longer than its more fortunate fellows left behind in their native haunts--and then only to wither and perish without requital? Know the orchid?--without the faintest idea of the veritable divorce which its kidnapping had involved!
Thanks to the new dispensation, we may indeed claim a deeper sympathy with the flower than is implied in a mere recognition of its pretty face. We know that this orchid is but the half of itself, as it were; that its color, its form, however eccentric and incomprehensible, its twisted inverted position on its individual stalk-like ovary, its slender nectary, its carefully concealed pollen--all are antic.i.p.ations of an insect complement, a long-tongued night-moth perhaps, with whose life its own is mysteriously linked through the sweet bond of perfume and nectar, and in the sole hope of posterity.
And the flower had been stolen from its haunt while its consort slept, and had awakened in a glazed prison--doubtless sufficiently comfortable, save for the absence of that one indispensable counterpart, towards whom we behold in the blossom"s very being the embodied expression of welcome.
Blooming day after day in antic.i.p.ation of his coming, and week after week still hoping against hope, we see the flower fade upon its stalk, and with what one might verily believe to be evidences of disconsolation, were it not that the ultra-scientist objects to such a sentimental a.s.sumption with regard to a flower, which is unfortunate enough to show no sign of nerves or gray matter in its composition. Who shall claim to _know_ his orchid who knows not its insect sponsor?
To take one of our own wild species. Here is the _Arethusa bulbosa_ of Linnaeus, for instance. Its pollen must reach its stigma--so he supposed--in order for the flower to become fruitful. But this is clearly impossible, as the pollen never leaves its tightly closed box unless removed by outside aid, which aid must also be required to place it upon the stigma. This problem, which confronted him in practically every orchid he met, Linnaeus, nor none of his contemporaries, nor indeed his followers for many years, ever solved.
Not until the time of Christian Conrad Sprengel (1735) did this and other similar riddles begin to be cleared up, that distinguished observer having been the first to discover in the honey-sipping insect the key to the omnipresent mystery. Many flowers, he discovered, were so constructed or so planned that their pollen could _not_ reach their own stigmas, as previously believed. The insect, according to Sprengel, enjoyed the anomalous distinction of having been called in, in the emergency, to fulfil this apparent default in the plain intentions of nature, as shown in the flower. Attracted by the color and fragrance of the blossom, with their implied invitation to the a.s.sured feast of nectar, the insect visited the flower, and thus became dusted with the pollen, and in creeping or flying out from it conveyed the fecundating grains to the receptive stigma, which they could not otherwise reach.
Such was Sprengel"s belief, which he endeavored to substantiate in an exhaustive volume containing the result of his observations pursuant to this theory.
But Sprengel had divined but half the truth. The insect _was necessary_, it was true, but the Sprengel idea was concerned only with the _individual_ flower, and the great botanist was soon perplexed and confounded by an opposing array of facts which completely destroyed the authority of his work--facts which showed conclusively that the insect could _not_ thus convey the pollen as described, because the stigma in the flower was either not yet ready to receive it--perhaps tightly closed against it--or was past its receptive period, even decidedly withered.
[Ill.u.s.tration]
This radical a.s.sumption of fertilization in the individual flower, which lay at the base of Sprengel"s theory, thus so completely exposed as false, discredited his entire work. The good was condemned with the bad, and the n.o.ble volume was lost in comparative oblivion--only to be finally resurrected and its full value and significance revealed by the keen scientific insight of Darwin (1859). From the new stand-point of evolution through natural selection the _facts_ in Sprengel"s work took on a most important significance. Darwin now reaffirmed the Sprengel theory so far as the necessity of the insect was concerned, but showed that all those perplexing floral conditions which had disproved Sprengel"s a.s.sumption, instead of having for their object the conveying of pollen to the stigma of the _same_ flower, implied its _transfer_ to the stigma of _another_, cross-fertilization being the evident design, or evolved and perpetuated advantage.
This solution was made logical and tenable only on the a.s.sumption that such evolved conditions, insuring cross-fertilization, were of distinct advantage to the flower in the compet.i.tive struggle for existence, and that all cross-fertilized flowers were thus the final result of natural selection.
The early ancestors of this flower were self-fertilized; a chance seedling at length, among other continual variations, showed the singular variation of ripening its stigma in advance of its pollen--or other condition insuring cross-fertilization--thus acquiring a strain of fresh vigor. The seedlings of this flower, coming now into compet.i.tion with the existing weaker self-fertilized forms, by the increased vigor won in the struggle of their immediate surroundings, and inheriting the peculiarity of their parent, showed flowers possessing the same cross-fertilizing device. The seeds from these, again scattering, continued the unequal struggle in a larger and larger field and in increasing numbers, continually crowding out all their less vigorous compet.i.tors of the same species, at length to become entire masters of the field and the only representatives left to perpetuate the line of descent.
Thus we find in almost every flower we meet some astonishing development by which this cross-fertilization is effected, by which the transferrence of the pollen from one flower to the stigma of another is a.s.sured, largely through the agency of insects, frequently by the wind and water, occasionally by birds. In many cases this is a.s.sured by the pollen-bearing flowers and stigmatic flowers being entirely distinct, as in cuc.u.mbers and Indian-corn; perhaps on different plants, as in the palms and willows; again by the pollen maturing and disseminating before the stigma is mature, as already mentioned, and _vice versa_.
From these, the simplest forms, we pa.s.s on to more and more complicated conditions, anomalies of form and structure--devices, mechanisms, that are past belief did we not observe them in actuality with our own eyes, as well as the absolutely convincing demonstration of the intention embodied: exploding flowers, shooting flowers, flower-traps, stamen embraces, pollen showers, pollen plasters, pollen necklaces, and floral pyrotechnics--all demonstrations in the floral etiquette of welcome and _au revoir_ to insects.
From the simplest and regular types of flowers, as in the b.u.t.tercup, we pa.s.s on to more and more involved and unsymmetrical forms, as the columbine, monk"s-hood, larkspur, aristolochia, and thus finally to the most highly specialized or involved forms of all, as seen in the orchid--the multifarious, multiversant orchid; the beautiful orchid; the ugly orchid; the fragrant orchid; the fetid orchid; the graceful, homely, grotesque, uncanny, mimetic, and, until the year 1859, the absolutely non-committal and inexplicable flower; the blossom which had waited through the ages for Darwin, its chosen interpreter, ere she yielded her secret to humanity.
And what is an orchid? How are we to know that this blossom which we plucked is an orchid? The average reader will exclaim, "Because it is an air-plant"--the essential requisite, it would seem, in the popular mind.
Of over 3000 known species of orchids, it is true a great majority are air-plants, or epiphytes--growing upon trees and other plants, obtaining their sustenance from the air, and not truly parasitic; but of the fifty-odd native species of the northeastern United States, not one is of this character, all growing in the ground, like other plants. It is only by the botanical structure of the flowers that the orchid may be readily distinguished, the epiphytic character being of little significance botanically.
A brief glance at this structural peculiarity may properly precede our more elaborate consideration of a few species of these remarkable flowers.
The orchids are usually very irregular, and six-parted. The ovary is one-celled, and becomes a pod containing an enormous yield of minute, almost spore-like, seeds (Fig. 3) in some species, as in the vanilla pod, to the number of a million, and in one species of the maxillaria, as has been carefully computed, 1,750,000.
The pollen, unlike ordinary flowers, is gathered together in waxy ma.s.ses of varying consistency, variously formed and disposed in the blossom, its grains being connected with elastic cobwebby threads, which occasionally permit the entire ma.s.s to be stretched to four or five times its length, and recover its original shape when released. This is noticeable specially in the _O. spectabilis_, later described. The grains thus united are readily disentangled from their ma.s.s when brought into contact with a viscid object, as, for instance, the stigma.
[Ill.u.s.tration: Fig. 1]
But the most significant botanical contrast and distinction is found in the union of the style and stamens in one organ, called the column (Fig.
2), the stigma and the pollen being thus disposed upon a single common stalk. The contrast to the ordinary flower will be readily appreciated by comparison of the accompanying diagrams (Fig. 1).
When, therefore, we find a blossom with the anthers or pollen receptacle united to a stalk upon which the stigma is also placed, we have an orchid.
The order is further remarkable, as Darwin first demonstrated in his wonderful volume "The Fertilization of Orchids," in that the entire group, with very few exceptions, are absolutely dependent upon insects for their perpetuation through seed. They possess no possible resource for self-fertilization in the neglect of these insect sponsors.
[Ill.u.s.tration: Fig. 2 a. Anther. s. Stigma.]
Many of our common wild flowers, as perfectly and effectually planned for cross-fertilization as the orchids, _do_ retain the reserve power of final _self_-fertilization if unfertilized by foreign pollen.
But the orchid has lost such power, and in the progress of evolution has gradually adapted itself to the insect, often to a particular species of insect, its sole sponsor, which natural selection has again gradually modified in relation to the flower.
The above work by Darwin was mostly concerned with foreign species, generally under artificial cultivation, and so startling were the disclosures concerning these hitherto sphinx-like floral beings that a most extensive bibliography soon attested the widespread inspiration and interest awakened by its pages.
But it is by no means necessary to visit the tropics or the conservatory for examples of these wonders. Our own Asa Gray, one of Darwin"s instant proselytes, was prompt to demonstrate that the commonest of our native American species might afford revelations quite as astonishing as those exotic species which Darwin had described.
[Ill.u.s.tration: Fig. 3]
During a period of many years the writer has devoted much study to our native species of orchids from this evolutionary stand-point of their cross-fertilization tendencies. Of the following examples, selected from his list, some are elaborations of previous descriptions of Gray and others, though pictorially and descriptively the result of direct original study from nature; others are from actual observation of the insects at work on the flowers; and others still, original demonstrations based upon a.n.a.logy and the obvious intention of the floral construction, the action of the insect--its head or tongue--having been artificially imitated by pins, bristles, or other probe-like bodies.