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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.

The viscid pollen-gland is here very peculiarly formed, elongated and pointed at each end, and it is not until we witness the act of its removal on the tongue of the butterfly that we can fully appreciate its significance.

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.

[Illustration: Fig. 13]

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.

[Illustration: Fig. 14]

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 of depending from the throat, grows upward from the lip, and, as we look at the flower directly from the front, completely hides the opening to the nectary, and an insect is compelled to insert its tongue on one side, which direction causes it to pass directly beneath the pollen disc, as in H. lacera, and with the same result.

[Illustration: Fig. 15]

Of all our native orchids, at least in the northeastern United States, the Cypripedium, or Moccasin-Flower, is perhaps the general favorite, and certainly the most widely known. This is readily accounted for not only by its frequency, but by its conspicuousness. The term "moccasin-flower" is applied more or less indiscriminately to all species. The flower is also known as the ladies'-slipper, more specifically Venus's-slipper-as warranted by its generic botanical title-from a fancied resemblance in the form of the inflated lip, which is characteristic of the genus. We may readily infer that the fair goddess was not consulted at the christening.

[Illustration]

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 mechanism of their cross-fertilization is the same in all, with only slight modifications.

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.

[Illustration]

The anthers in this genus, then, are two, instead of the previous single anther with its two pollen-cells. The pollen is also quite different in its character, being here in the form of a pasty mass, whose entire exposed surface, as the anther opens, is coated with a very viscid gluten.

[Illustration: Fig. 16]

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.