Let us take the OAT (Avena sativa, fig. 1), as our present illustration. Here you will not find, as we have done in all the other flowers that we have hitherto examined, the stamens and pistils enclosed in envelopes, arranged cirucularly round them. In the Oat, it is true, these organs are protected, not, however, by a circular envelope, but by small scales which, instead of being, placed on a level, are above each other in such a way that the inferior encloses the superior placed opposite it.

Remove a flower (fig. 2); you first meet with two leaves or pointed scales (GL, GL), nearly equal, and which seem placed at the same height; but on closer observation you will find that the one is lower than the other, and that the lower encloses the highter one. This will be more apparent in a flower that is not fully expanded. If you remove these two scales there remains a flattened body pointed at the summit, bearing on the middle of its back a stiff and brittle awn (A), which falls off in time.

Press this body between your fingers, and with the point of your penknife open the scale upon which the awn is place, and you will see that this scale encloses another much smaller (PL), the summit of which is not pointed, and the back of which does not carry a scale, and which is placed on a stalk opposite and a little above the large scale, in which it is completely enveloped. When you have thus removed it, you will see the organs in the centre of the flower (fig. 3). These are, first, three stamens, with very slender filaments (F), the anthers of which (A) have the form of a very long X, and opening by two slits. In the centre of them is a small oval body (0), which is the ovary, and it is surmounted by two fine feathery stigmas, on which the pollen is deposited.

Before removing the smaller of the scales, you ought to observe the small body on a slender stalk (fig. 2, FS). this is an undeveloped flower, of which we shall speak in a future lesson.

Let us now turn our attention to a very different kind of flower to any we have yet had to deal with. It is that of the Pine (Pinus sylvestris), or Scotch Fir. Here, as in the Oak, the stamens and pistil are on the same tree, but in separate flowers.

We shall study in a future lesson the structure and development of the female flower. For the present we may state that they are of a vinous red colour when young, and form a small conical head composed of numerous scales. These scales cover each other like the tiles of a house; and when young they are distant from each other, but as they increase in size they become enlarged at the superior extremities, with a small point in the centre of the enlargement.

As to the stamens, the duration of which is very short, they are in a dense mass, and abound in pollen. to study them properly it is necessary first to shake the branch on which they grow, and the dust will escape from them in clouds. You will then see a sort of dense spike, composed of yellow heads, which are placed immediately on the branch that bears them. Each head contains about a score of anthers (fig. 4), which, when examined by the aid of a magnifying glass, after detaching one of them with your penknife, you will see it contains a double cell, opening as in most of the flowers we have examined. This cell is fixed by its back to the scale.

Each head is furnished at its base with three transparent and united scales: outside of this is another, thick, short, and concave. Besides, the base of the cluster is furnished with numerous brown scales, which enclose it before it is developed. At the extremity of this cluster you see small shoots, covered with yellowish scales, which later become leaves.

In the flowers of the Pine, as in those of the Oat, you have not found any regular circular envelope; the stamens and the pistil being protected only by scales.

As our last study take the Cuckoo-pint (Arum maculatum). Here there are no circular envelopes, neither interior nor exterior; not even scales to protect the organs of reproduction.

These organs, however, are not entirely naked, as you shall see. Observe, in fact, a large leaf of a yellowish gree colour, folded like a horn; this is swollen in its inferior part. You will perceive a sort of club of a purplish colour, gracefully erect in the centre of the cavity, round which the leaf is folded. If, now, you open this leaf towards the base (fig. 5), you will meet with a complicated arrangement of organs. Quite at the base are the ovaries, fixed close on the stalk, and placed round it in several series, each of them terminating in a bearded neck. Above them are the stamens, their anthers without filaments; they also are placed immediately on the stem, and arranged in more numerous series.

Above these are two or three series of pointed bodies; these are undeveloped anthers; and above all is the purple club.

During a certain period, when the plant is in bloom, the club acquireds a considerable heat, sensible to the hand, and still more so to the thermometer. This heat begins commonly between two and three o'clock in the afternoon, its highest degree being between six and eight o'clock, and at ten it ceases. The club becomes blackish during this phenomenon, by which it may be ascertained when it is in operation.