A Pine Branch
Initial S everal of our notable as well as notorious human, social, and civic customs find their prehistoric prototypes in the insect kingdom. The monarchical institution sees its singular prophecy in the domestic economy of the bees. War and slavery have always been carried on systematically and effectually by ants, and, according to Huber and other authorities, agriculture, gardening, and an industry very like dairy farming have been time-honored customs among this same wise and These are only a few of the more notable parallelisms which suggest themselves. But others are not wanting if we care to follow the subject. In addition to the many models of thrift and virtuous industry, embodying types of many of the trade employments known to humanity, have we not also among these "meadow tribes" our luxurious "idlers" and "exquisites," the butterflies and flower-haunting flies and "dandy" beetles; and, opposed to all these, the suggestive antithesis of the promiscuous marauders, thieves, and brigands everywhere interspersed? Thus we have our individual insect assassin and assassination organized in war; so, on the other hand, have we our insect merrymakers; why not, then, our picnic or carnival? Such I am moved to call the singular episode which I observed last summer, and which I have endeavored to picture as true to the life as possible in the accompanying presentment The scep One July afternoon a year ago I was returning home from one of my botanizing strolls. I had just emerged from a deep wood, and was skirting its border, when my attention was caught by a small fluttering swarm of butterflies, which started up at my approach and hovered about a blossoming blackberry bush a few yards in advance of me at the side of my path. The diversity of the butterfly species in the swarm struck me as singular, and the mere allurement of the blackberry blossoms—not usually of especial attraction to butterflies—could hardly explain so extensive a gathering. Here was the great yellow swallow-tail (Turnus), red admiral (Atlanta), small yellow butterfly (Philodice), white cabbage-butterfly, comma and semicolon, and numerous small fry, fluttering about me in evident protest against my intrusion. They showed no inclination to vacate the Carefully stealing through the tall grass, I now approached to within touching distance of the haunt, and was soon lost in mingled wonder, amusement, and surprise at the picnic now disclosed, the occasional butterfly swarm being now easily explained. From my first point of view only the top of the bramble spray was visible above the grass, and by far the most interesting portion of the exercises had been concealed from view. The butterflies, while naturally the most conspicuous element, were now seen to be in a small minority among the insect gathering, the bramble leaves being peopled with a most motley and democratic assemblage of insects. Class distinctions were apparently forgotten in the common enthusiasm; the plebeian bluebottle and blowfly now consorted with Aphrodite and sipped at the same drop. Many a leaf was begemmed with the blue bodies closely set side by side or in a close cluster. The meat-fly, house-fly, and horse-fly made themselves promiscuous in every portion of the spray, and what with the rainbow-eyed and ruby-eyed flies, black and silver-banded flower-flies, and other tiny, restless, iridescent atoms of the fly fraternity, the family of Musca was well represented at the feast. Nor were these all the guests at the banquet I have no direct means of knowing as to the social discrimination of the host as shown in the entertainment, for that invitations were issued the subsequent facts would show. But I have good reasons for believing, from the course of events, that the gathering included a number of questionable personages that were not counted upon. Here, for instance, was an overwhelming contingent of the whole tough gang of wasps and hornets—brown wasps from under the eaves and fences; black hornets from the big paper nests; yellow-jackets from where you please; deep steel-blue wire-waisted wasps from the mud cells in the garret, to say nothing of an occasional longer-waisted digger-wasp, and a host of their allied lesser associates scattered around generously among the assemblage. Every now and then a big darning-needle took a shimmering circuit about the bush, and doubtless knew what he was about; as did also what at first glimpse appeared to be a big bumblebee, which seemed to find attraction in the neighborhood, although he seldom alighted upon the I have thus described a few of the more prominent guests or personages present at the feast. But I have reported little of their "goings on." Doubtless there were appropriate toasts and responses, or what in bug etiquette answered to this seemingly indispensable human fad, while as to that other festive social essential of after-dinner speeches, coupled in this case with most vigorous discussion, I am certain the air was blue with something of this sort, if the eloquent pantomime bore any significance. Here, for instance, is one isolated, but frequent, episode. A peaceable little group of plain bluebottle-flies, with but a single thought, are all sipping at the same drop in contentment. A brief respite, for now the tips of a pair of inquisitive antennÆ appear from the under edge of the leaf upon which they are sipping, and gingerly explore the upper surface. They are quickly followed by the covetous almond-eyed gaze of a brown wasp, that now steals cautiously around to the upper surface, and appears wholly engrossed in licking the leaf. Nearer and nearer he sidles up to the group of flies, and now with deliberate purpose and open jaws makes a dash among them. But they are too quick for him, Another and another of these friendly meetings between them and other wasps took place in the half-hour in which I watched the sport. There were lulls in hostilities, during which an atmosphere of perfect peace and harmony seemed to reign around my bramble-bush. The flies were motionless in their ecstasy, and the hornet element seemed by common consent to keep temporarily shady, and even the butterflies seemed to The Picnic The Picnic And now my pretty black butterfly—no, it proved to be the little day-flying grape-vine-moth, the eight-spotted black Alypia—appeared from some unseen source, and spun his crapy white- Here is a pretty little yellow and black banded flower-fly, which is having a quiet little picnic all by himself on a bed of yarrow bloom close by. But a big black paper-hornet has suddenly seen an attraction hither also, and is soon creeping stealthily among the blossoms with a wild and hungry look. But the hornets seemed to waste their time on the flies. Seemingly confident in their less complicated wing machinery, the two-winged fly rarely sought escape until within very close range of his enemy, and his resources never seemed to disappoint him at the critical moment. Among the insect assemblage was a large number of ants of all kinds and sizes, the common On the same stem a big blowfly has alighted. Judging from appearances, he has had his fill of good things, and is now making his leisurely toilet in the peculiar fashion of his kind, rubbing down his back and wings with his hind legs, twisting his front feet into spirals, and ever and anon testing the strength of his elastic neck attachment as he threatens to pull his head from his body. This worldly act has been progressing for some moments under the gaze of a big black digger-wasp, who now concludes to cut it short. When at close range with his prey, the fly suddenly discovers the unhealthy location which he occupies, and actually protruding his tongue by way of parting salute, he is off with a buzz. He has barely taken wing, however, when a still louder buzz is heard, while a great black bumblebee follows closely in his wake, until the sounds of both And what is this? A yellow-jacket has found an ambrosial attraction here upon the bramble leaf. Meanwhile a great black and white paper-hornet has seen his opportunity, and is soon slyly approaching behind the sipper. That he has designs on that jacket and its contents is apparent. In a moment the onslaught is consummated, and in the struggle which ensues the black assailant 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 butterfly wings strewed the grassy 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 space being surrounded by a colony of aphides, or plant-lice, from whose distilling pipes the rain of sweet honey-dew had 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 antennÆ while they sipped at the honeyed pipes everywhere upraised in most expressive and harmonious welcome. This intimate and friendly association 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
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 illustra 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 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 LinnÆus 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 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 anticipations 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 anticipation of his coming, and week after week still hoping against To take one of our own wild species. Here is the Arethusa bulbosa of LinnÆus, 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, LinnÆus, 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 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. Arethusa Bulbosa Arethusa Bulbosa This radical assumption 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 noble 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 assumption, 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 assumption that such evolved conditions, insuring cross-fertilization, were of distinct advantage to the flower in the competitive 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 competition 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 competitors 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 assured, largely through the agency of insects, frequently by the wind and water, occasionally by birds. In many cases this is assured by the pollen-bearing flowers and stig From these, the simplest forms, we pass 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 buttercup, we pass 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 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 Fig. 1. The Botanical Distribution of an Ordinary Flower and of the Orchid Fig. 1. The Botanical Distribution of an Ordinary Flower and of the Orchid The pollen, unlike ordinary flowers, is gathered together in waxy masses of varying consistency, variously formed and disposed in the blossom, its grains being connected with elastic cobwebby threads, which occasionally permit the entire mass 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 mass when brought into contact with a viscid object, as, for instance, the stigma. 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 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. The "Column" in Various Orchids Fig. 2. The "Column" in Various Orchids 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 selec 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. Fig. 3. The Result of the Bee's Visit Fig. 3. The Result of the Bee's Visit 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 elabora How many an enthusiastic flower-hunter has plucked his fragrant bouquet of the beautiful Arethusa, in its sedgy haunt, without a suspicion of the beautiful secret which lay beneath its singular form! Indeed, how many a learned botanist, long perfectly familiar with its peculiarities of shape and structure, has been entirely content with this simple fact, nor cared to seek further for its interpretation! But "All may have the flower now, With Darwin as our guide and the insect as our key—an open sesame—the hidden treasure is revealed. It is now quite possible, as Darwin demonstrated, to look upon a flower for the first time and from its structure foretell the method of its intended cross-fertilization; nay, more, possibly Let us look at our Arethusa. The writer has never happened to observe an insect at work upon this flower, but the intention of its structure is so plain that by a mere examination we may safely prophesy not only what must happen when the insect seeks its nectar, but with equal assurance the kind of insect thus invited and expected. I have indicated a group of the orchids in their usual marshy haunt, and in Fig. 4, separately, a series of diagrams presents sections of the flower, natural size and duly indexed, which renders detailed description hardly necessary. The column is here quite elongated, forked at the tip, the space between the forks occupied by the anther, which is hinged to the upper division. This anther lid is closed tightly, with the sticky mass of pollen hidden behind it in the cavity. The stigma is on the external inner side of the lower division, and thus distinctly separated from the pollen. The "lip" is extended forward as a hospitable threshold to the insect. And to what insect might we assume this invitation of color, fragrance, nectar, and threshold to be extended? Let us consider the flower simply as a device to insure its own cross-fertilization. The insect Fig. 4. Cross-fertilization of Arethusa Fig. 4. Cross-fertilization of Arethusa The diagrams (Fig. 4) sufficiently illustrate the efficacy of the beautiful plan involved. At A the bee is seen sipping the nectar. His forward movement thus far to this point has only seemed to press the edge of the anther inward, and thus keep it even more effectually closed. As the bee retires (B), the backward motion opens the lid, and the sticky pollen is thus brought against the insect's back, where it adheres in a solid mass. He now flies to the next Arethusa blossom, enters it as before, and in retiring slides his back against the receptive viscid stigma, which retains a portion of the pollen, and thus effects the cross-fertilization (C). Professor Gray surmised that the Fig. 5. Habenaria Orbiculata. A Single Flower Enlarged Fig. 5. Habenaria Orbiculata. A Single Flower Enlarged Having thus had one initiation into this most enticing realm of riddles, each successive orchid whose structure we examine from this stand-point becomes a most interesting, perhaps a fresh, problem, whose assumed solution may often be verified by studying the insect in its haunts. Darwin thus foretold the precise manner of the cross-fertilization of Habenaria mascula, and also the insect agent, simply by the structural prophecy of the flower itself. Suppose, for example, an unknown orchid blossom to be placed in our hands. Its nectary tube is five inches in length, and as slender as a knitting-needle. The nectar is secreted far within its lip. The evolution of the long nectary implies an adaptation to an insect's tongue of equal length. What insect has a tongue five inches long, and sufficiently slender to probe this nec In our own native orchids we have a remarkable example of the latter form in the Habenaria orbiculata, whose structure and mechanism have also been admirably described by Asa Gray. All orchid-hunters know this most exceptional example of our local flora, and the thrill of delight experienced when one first encounters it in the mountain wilderness, its typical haunt, is an event to date from—its two great, glistening, fluted Orchis Spectabilis Orchis Spectabilis Fig. 6. Cross-fertilization of H. Orbiculata (Sphinx-moth) Fig. 6. Cross-fertilization of H. Orbiculata (Sphinx-moth) A single blossom of the species is shown in Fig. 5, the parts indexed. The opening to the nectary is seen just below the stigmatic surface, the nectary itself being nearly two inches in length. The pollen is in two club-like bodies, each hidden within a fissured pouch on either side of the stigma, and coming to the surface at the base in their opposing sticky discs as shown. Many of the group Habenaria or Platanthera, to which this flower belongs, are similarly planned. But mark the peculiarly logical association of the parts here exhibited. The nectary implies a welcome to a tongue two inches long, and will reward none other. This clearly shuts out the bees, butterflies, and smaller moths. What insect, then, is here implied? The sphinx-moth again, one of the lesser of the group. A larger individual might sip the nectar, it is true, but its longer tongue would reach the base of the tube without effecting the slightest contact with the pollen, which is of course the desideratum here embodied, and which has reference to a tongue corresponding to the length of the nectary. There In effecting the cross-fertilization of one of the younger flowers its eyes are again brought into contact with this second pair of discs, and these, with their pollen clubs, are in turn withdrawn, at length perhaps resulting in such a plastering of the insect's eyes as might seriously impair its vision, were it not fortunately of the compound sort. Fig. 7. The Flower and Column of Orchis Spectabilis, Enlarged Fig. 7. The Flower and Column of Orchis Spectabilis, Enlarged In another allied example of the orchids—the Showy Orchid—we have, however, what would appear a clear adaptation to the head of a bee, Fig. 8. Orchis Spectabilis Fig. 8. Orchis Spectabilis Fig. 9. Position of Pollen of Orchis Spectabilis Withdrawn on Pencil Fig. 9. Position of Pollen of Orchis Spectabilis Withdrawn on Pencil I have seen many specimens with the pollen masses withdrawn, and others with their stigmas well covered with the grains. Though I have never seen an insect at work upon it in its haunt, the whole form of the opening of the flower would seem to imply a bee, particularly a bumblebee. If we insert the point of a lead-pencil into this opening, thus imitating the entrance of a bee, its bevelled surface comes in contact with the viscid discs by the rupture of a veil of membrane, which has hitherto protected them. The discs adhere to the pencil, and are withdrawn upon it (Fig. 9). At first in upright position, they soon assume the forward inclination, as previously described. The nectary is about the length of a bumblebee's tongue, and is, moreover, so amply expanded at the throat below the stigma as to comfortably admit its wedge-shaped head. The three progressive diagrams (Fig. 10) indicate the result in the event of such a visit. The pollen discs are here very close together, and are protected within a membraneous cup, in which they sit as in a socket. As the insect inserts his head at the opening (A) it is brought against this tender membrane, which ruptures and exposes the viscid glands of the pollen masses, which become instantly attached to the face or In the case of a smaller bee visiting the flower, the insect would find it necessary to creep further into the opening, and thus might bring its thorax against the pollen-glands. In either case the change of position in the pollinia would insure the same result. Fig. 10. The Cross-fertilization of Orchis Spectabilis Fig. 10. The Cross-fertilization of Orchis Spectabilis Fig. 10. The Cross-fertilization of Orchis Spectabilis Fig. 10. The Cross-fertilization of Orchis Spectabilis We have thus seen adaptation to the thorax, the eyes, and the face in the three examples given. And the entrance of the flower in each instance is so formed as to insure the proper angle of approach for the insect for the accomplishment of the desired result. This direct approach, so necessary in many orchids, is insured by various devices—by the position of the lip upon which the insect must alight; by the narrowed entrance of the throat of the flower in front of the nectary; by a fissure in the centre of the lip, by which the tongue is conducted, etc. Many other species allied to the above possess similar devices, with slight variations; and there is still another group whose structure is distinctly adjusted to the tongues of insects—adaptations not merely of position of pollen masses, but even to the extent of a special modification in the entrance to the flower and the shape of the sticky gland, by which it may more securely adhere to that sipping member. In the common pretty Purple-fringed Orchid, Fig. 11. The Purple-fringed Orchid Fig. 11. The Purple-fringed Orchid If, however, the butterfly should approach directly in front of the flower, as in a larger blossom he would be most apt to do, he might sip the nectar indefinitely and withdraw his tongue without bringing it in contact with the viscid pollen discs. But in the dense crowding of the flowers, over which the insect flutters indiscriminately, the approach is oftenest made obliquely, and thus the tongue brushes the disc on the side approached, and the pollen mass is withdrawn. But an examination of this orchid affords no pronounced evidence of any specific intention. There is no unmistakable sign to demonstrate which approach is In another closely allied species, however, we have a distinct provision which insures the proper approach of the tongue—one of many similar devices by which the tongue is conducted directly to one or the other of the pollen discs. Fig. 12. The Ragged Orchid (Front Section) Fig. 12. The Ragged Orchid (Front Section) This is the Ragged Orchid, a near relative of the foregoing, H. psycodes, but far less fortunate in its attributes of beauty, its long scattered spike of greenish-white flowers being so inconspicuous in its sedgy haunt as often to conceal the fact of its frequency. Its individual flower is shown enlarged at Fig. 12—the lip here cut with a lacerated fringe (H. lacera). The pollen-pouches approach slightly at the base, directly opposite the nectary, where the two viscid pollen-glands stand on guard. Now were the opening of the nectary at this point unimpeded, the same condition The throat of the nectary, thus centrally divided, presents two small lateral openings, each of which, from the line of approach through the much-narrowed entrance of the flower, is thus brought directly beneath the waiting disc upon the same side. The structure is easily understood from the two diagrams Figs. 12 and 13, both of which are indexed. Fig. 13. The Ragged Orchid (Profile Section) Fig. 13. The Ragged Orchid (Profile Section) The viscid pollen-gland is here very peculiarly formed, elongated and pointed at each end, and it I have often seen butterflies at work upon this orchid, and have observed their tongues generously decorated with the glands and remnants of the pollen masses. The series of diagrams (Fig. 14) will, I think, fully demonstrate how this blossom utilizes the butterfly. At A we see the insect sipping, its tongue now in contact with the elongated disc, which adheres to and clasps it. The withdrawal of the tongue (B) removes the pollen from its pouch. At C it is seen entirely free and upright, from which position it quickly assumes the new attitude shown at D. As the tongue is now inserted into the subsequent blossom this pollen mass is thrust against the stigma (E), and a few of the pollen grains are thus withheld upon its viscid surface as the insect departs (F). In this orchid we thus find a distinct adaptation to the tongue of a moth or butterfly. Another similar device for assuring the necessary side approach is seen in H. flava (Fig. 15), a yellowish spiked species, more or less common in swamps and rich alluvial haunts. Fig. 14. The Ragged Orchid (H. Lacera) and the Butterfly's Tongue. Cross-fertilization Fig. 14. The Ragged Orchid (H. Lacera) and the Butterfly's Tongue. Cross-fertilization Professor Wood remarks, botanically, "The tubercle (or palate) of the lip is a remarkable character." But he, too, has failed to note the equally remarkable palate of the ragged orchid, just described, both provisions having the same purpose, the insurance of an oblique approach to the nectary. In H. flava this "tubercle," instead Fig. 15. The Yellow Orchid (H. Flava) Fig. 15. The Yellow Orchid (H. Flava) The Ragged Orchid (H. Lacera) The Ragged Orchid (H. Lacera) Of all our native orchids, at least in the northeastern United States, the Cypripedium, or Moc There are six native species of the cypripedium in this Eastern region, varying in shape and in color—shades of white, yellow, crimson, and pink. The most common of the group, the C. acaule, most widely known as the moccasin-flower, whose large, nodding, pale crimson blooms we so irresistibly associate with the cool hemlock woods, will afford a good illustration. The lip in all the cypripediums is more or less sac-like and inflated. In the present species, C. acaule, however, we see a unique variation, this portion of the flower being conspicuously bag-like, and cleft by a fissure down its entire anterior face. In Fig. 16 is shown a front view of the blossom, showing this fissure. The "column" (B) in the cypripedium is very distinctive, and from the front view is very non-committal. It is only as we see it in side section, or from beneath, that we fully comprehend the disposition of stigma and pollen. Upon the stalk of this column there appear from the front three lobes—two small ones at the sides, each of which hides an anther attached to its under face—the large terminal third lobe being in truth a barren rudiment of a former stamen, and which now overarches the stigma. The relative position of these parts may be seen in the under view. Cypripedium Acaule Cypripedium Acaule The anthers in this genus, then, are two, instead Fig. 16. Moccasin-flower (C. Acaule) Fig. 16. Moccasin-flower (C. Acaule) With the several figures illustrating the cross-fertilization, the reader will readily anticipate any description of the process, and only a brief commentary will be required in my text. I have repeatedly examined the flowers of C. acaule in their haunts, have observed groups wherein every flower still retained its pollen, others where one or both pollen masses had been withdrawn, and in several instances associated with them I have observed the inflated lip most outrageously bruised, torn, and battered, and occasionally perforated by a large hole. I had ob Fig. 17. The Bee Imprisoned in the Lips of Cypripedium Fig. 17. The Bee Imprisoned in the Lips of Cypripedium At length, in hopelessness of reward by such means, I determined to see the process by more prosaic methods. Gathering a cluster of the freshly opened flowers, which still retained their pollen, I took them to my studio. I then captured a bumblebee, and forcibly persuaded him to enact the demonstration which I had so long waited for him peaceably to fulfil. Taking him by the wings, I pushed him into the fissure by which he is naturally supposed to enter without persuasion. He was soon within the sac, and the inflexed wings of the margin had closed above him, as shown in section, Fig. 17. He is now enclosed in a luminous prison, and his buzzing protests are audible and his vehemence visible from the outside of the sac. Let us suppose that he Such, with slight modifications, is the plan evolved by the whole cypripedium tribe. Darwin mentions bees as the implied fertilizers, and doubtless many of the smaller bees do effect cross-fertilization in the smaller species. But the Fig. 18. The Bee Passing Beneath the Stigma Fig. 18. The Bee Passing Beneath the Stigma Occasionally I suppose a fool bumblebee is entrapped within the petal bower and fails to find the proper exit, or it may be—much less a fool—having run the gantlet once too often, decides to escape the ordeal; hence the occasional mutilated blossom already described. One of the most beautiful of our orchids, though its claims to admiration in this instance are chiefly confined to the foliage, is the common "Rattlesnake-Plantain," its prostrate rosettes of exquisitely white reticulated leaves carpeting many a nook in the shadows of the hemlocks, its dense spikes of yellowish-white blossoms signalling their welcome to the bees, and fully compen Fig. 18. Bee Receiving Pollen-plaster on His Thorax Fig. 18. Bee Receiving Pollen-plaster on His Thorax The single flower is shown enlarged in Fig. 19—A, a young blossom, with analyses B and C, the latter indexed; D, an older blossom, with similar analyses (E and F). Both sorts are to be found upon every spike of bloom, as the inflorescence begins at the base and proceeds upward. As we look into the more open flower we observe a dark-colored speck, which, by analysis, proves to be the lid of the anther. This portion is further shown enlarged in Fig. 20, A. If we gently lift it with a pin, we disclose the pollen masses in the cavity (B) thus opened (C, profile section), the two pairs united to a common viscid gland at the base, this gland again secreted behind a veil of moist membrane, as also shown at B. This membrane is, moreover, very sensitive to the touch. Below the flattened tip of the column, and at a sharp inward angle, is the stigma. In the Fig. 19. Rattlesnake-Plantain the Young and the Old Fig. 19. Rattlesnake-Plantain the Young and the Old Fig. 21. Cross-fertilization of the Rattlesnake-Plantain. Side Sections Fig. 21. Cross-fertilization of the Rattlesnake-Plantain. Side Sections The further demonstration will be better shown by profile sections (Fig. 21). Nectar is secreted in the hollow of the lip indicated, somewhat as in the cypripedium. If we now imitate with a probe the habit of the insect and the action of its tongue, we may witness a beautiful contrivance for cross-fertilization. We will suppose the bee to Fig. 20. Cross-fertilisation of the Rattlesnake-Plantain. Front View Fig. 20. Cross-fertilisation of the Rattlesnake-Plantain. Front View The Tongue of a Bumblebee The Tongue of a Bumblebee In the allied Spiranthes, or "Lady's-Tresses," a somewhat similar mechanism prevails, by which fertilization is largely effected by the changed position or angle of the stigma plane. And thus we might proceed through all the orchid genera, each new device, though based upon one of the foregoing plans, affording its new surprise in its special modification in adaptation to its insect sponsor—all these various shapes, folds of petals, positions, colors, the size, length, and thickness of nectary, the relative positions of pollen and stigma, embodying an expression of welcome to the insect with which its life is so marvellously linked. Occasionally this astounding Among the host of sceptics—and were they not legion?—who met this evolutionary and revolutionary theory with incredulity, not to say ridicule or worse, was one who thus challenged its author shortly after the appearance of his "Fertilization of Orchids," addressing Darwin from Madagascar substantially as follows: "Upon your theory of evolution through natural selection all the various contrasting structural features of the orchids have direct reference to some insect which shall best cross-fertilize them. If an orchid has a nectary one inch long, an insect's tongue of equivalent length is implied; a nectary six inches in length likewise implies a tongue six inches long. What have you to say in regard to an orchid which flourishes here in Madagascar possessing a Darwin's reply was magnificent in its proof of the sublime conviction of the truth of his belief: "The existence of an orchid with a slender nectary eleven inches in length, and with nectar secreted at its tip, is a conclusive demonstration of the existence of a moth with a tongue eleven inches in length, even though no such moth is known." Many of us remember the ridicule which was heaped upon him for this apparently blind adherence to an untenable theory. But victory complete and demoralizing to his opponents awaited this oracular utterance when later a disciple of Darwin, led by the same spirit of faith and conviction, visited Madagascar, and was soon able to affirm that he had caught the moth, a huge sphinx-moth, and that its tongue measured eleven inches in length. Goodyera, or Periamium Pubescens Goodyera, or Periamium Pubescens Here we see the prophecy of the existence of an unknown moth, founded on the form of a blossom. At that time the moth had not been actually seen at work on the orchid, but who shall The AngrÆcum also affords in this long pendent nectary a most lucid illustration of the present workings of natural selection. The normal length of that nectary should be about eleven inches, but in fact this length varies considerably in the flowers of different plants, this tendency to Again, let us suppose the variation of an extra long nectary, and the writer recently saw a number of these orchids with nectaries thirteen inches in length. The moth comes, and now must needs insert its head to the utmost into the opening of the flower. This would insure its fertilization by the pollen on the insect's tongue; and even though the sipper failed to reach the nectar, the pollen would be withdrawn upon the tongue, to be carried to other flowers, which might thus be expected to inherit from the paternal side the ten |