Note the why and wherefore of this departure from orthodox arrangements of floral organs. At the bottom of the flower-tube honey is secreted, and to obtain this the flower is visited by humble-bees. In order that his long tongue may reach the honey, the bee has to push his head and back against the stigma and the anther. If he has previously visited a flag-flower his back will be covered with pollen, some of which will adhere to the stigma. He will also take away on his head and back some of the pollen from the flower he is now visiting, and will fertilize other flags with it.
There is another British species,—
The Stinking Iris, Gladdon, or Roast-beef plant (Iris fœtidissima), with purple sepals, yellow petals and stigmas. Flowers not quite so large as the last. Woods and copses. May to July.
Lucerne, Purple Medick.
Medicago sativa.
—Leguminosæ.—
Yellow Iris. Flag.
Iris pseudacorus.
—Irideæ.—
Marsh Orchis (Orchis latifolia).
There are nearly forty British species of Orchideæ, divided into sixteen genera; and in the space at our disposal it is impossible to give anything like an adequate account of the group or of the specific characters. An attempt will be made, however, to make the reader acquainted with the general structure by means of three figures. The first of these represents the Marsh Orchis (O. latifolia), a species commonly to be met in wet meadows and marshy places, flowering from May to July. The two tubers are palmate, that is, more or less flattened like a hand, and terminating in finger-like processes. The leaves chiefly spring from the summit of one of these tubers, the lowest acting as sheath for the next, and so on, the tubular flower-stem rising through all the sheaths. The leaves are oblong, and spotted with purple. The inflorescence is a spike, the flowers crowded upon it, but separated by the long three-nerved green bracts. The structure of these flowers will be found to differ widely from all we have considered in these pages. The perianth is placed above the (consequently inferior) ovary, which is twisted. This twist, it will be well to bear in mind, brings the flower “upside down.” The three sepals and the three petals are equally coloured, and it is therefore convenient to speak of them as the perianth. There is only one stamen, which is supported by the pistil. Two of the perianth leaves combine to form a hood over the stamen, and a third is greatly larger than the others, divided into three lobes and hanging down like the lip of a labiate flower. This is known as the labellum, and it is continued backwards and downwards as a hollow spur, in which, however, honey is not secreted. At the top of this spur, at the back, is the stigmatic surface, and above it protrudes a fleshy knob, called the rostellum, which supports the anther. This organ consists of two lobes, side by side, which open in front, and reveal in each a mass of pollen grains tied together by elastic threads and attached to a slender foot-stalk with a sticky base. This is a tedious description, though we have made it as brief as possible. The reader shall see the reason for it if he will conduct a little experiment. We may premise that these orchids are fertilized by long-tongued insects, who suck the juice through the tender skin lining the spur.