(epiphyllous) at the base of the limb, as in Dracæna. Crinum has therefore Perianth superior, gamophyllous. Stamens epiphyllous, hexandrous. FIG. 38. Flower of Crinum. 4. DRACENA (any cultivated species). The leaves of the perianth, six in number, resemble each other in size and form. The perianth is therefore regular. As the leaves of the perianth cohere by their margins to about half their length, forming a short tube, the perianth is gamophyllous. As it is wholly free from the ovary, it may be described as inferior. There are six stamens inserted upon the perianth and opposite to its six segments, there being two whorls of three each: the three outer stamens alternating with the three inner segments FIG. 39. Flower of Dracena; a vertical section. of the perianth; the three inner stamens alternating with the three outer stamens, consequently opposed to the three inner perianth-segments, as in like manner are the three outer stamens opposed to the three outer perianthsegments. The pistil has a three-lobed stigma and a threecelled ovary. Dracæna may be described thus :— Perianth inferior, gamophyllous. Stamens perigynous, hexandrous. 5. WHEAT. We have here an arrangement of parts widely different from that obtaining in any of the plants hitherto examined. The flowers are arranged in short, broad, sessile spikelets, which spikelets are disposed alternately in two rows along the top of the stem, forming a dense obtusely four-cornered spike. Break the entire spike in two about the middle, and take one of the lowest spikelets from the upper half. Observe that it is attached to the stem (axis of the spike, called the rachis) by its side. In some grasses, as Rye-grass, the spikelets are attached by their edge to the rachis. Each spikelet consists of a pair of nearly opposite, hard, dry, scaly leaves, called the outer glumes, which enclose three to five closely imbricated flowers, arranged alternately on opposite sides of the axis of the spikelet. Each flower is enclosed between a flowering-glume and a pale. The flowering-glume and pale are opposite to each other, and inserted very nearly at the same point: the flowering-glume, however, is the lower, and usually embraces the pale with its incurved edges. It is similar in form and texture to the outer glumes, and often terminates in a bristle (awn). The pale is generally easily distinguished by its having two lateral nerves and no midrib, indicating, apparently, that it may be composed of two organs cohering together. Between the floweringglume and the pale are the three free stamens and the superior ovary crowned with two plume-like stigmas. Note also two very minute scales, called lodicules, representing a perianth, inserted under the ovary. Between the outer glumes and the lowest flowering-glume of the spikelet in some grasses, Fig. 40. The two outer glumes of a spikelet and the parts of a single floret of Wheat. The two lowest scales, right and left, are the outer glumes; of the next pair, the scale to the right is the flowering-glume, that to the left the pale. Then come the two minute lodicules, the three stamens, and the pistil. and, in others, above the uppermost perfect flower of the spikelet, there are one or more empty glumes, which are called, by some botanists, sterile flowers. Occasionally a staminate flower is borne in the axil of the glume next below or above the perfect flower. Wheat may be thus described :— Spikelets sessile, with two outer glumes. Flowers with one flowering-glume, one pale, two lodicules. Stamens triandrous, hypogynous. Pistil syncarpous, ovary superior. 6. Let us now proceed to review, as before, the five plants last examined, viz. Colocasia, Dendrobe, Crinum, Dracæna, and Wheat. They all happen to be herbaceous plants. The leaves, excepting in Colocasia, although narrowed below more or less, do not present an abrupt distinction of petiole and blade, and, with the same exception, the veins of the leaves are parallel and not irregularly netted. Those which have the essential organs of the flower enclosed in a perianth have the leaves which compose it arranged in two whorls (corresponding to calyx and corolla respectively) of three each. We find our plants generally marked by (1) the absence of any abrupt distinction between blade and petiole; (2) parallel-veined leaves; and (3) the parts of the flowers in threes. 7. We must now soak a few grains of Wheat for comparison with the seeds of Dicotyledons. We must, however, be careful not to regard the grain of Wheat as a seed corresponding to that of the Pea or Orange, for it is a fruit, consisting of pericarp (ovary) and seed; the pericarp being closely adherent to the true seed. In the Crinum, FIG. 41. Longitudinal section of a Grain of Wheat. The embryo is represented at the base of the Seed. Dracena, and other plants just examined, the seeds are free from the pericarp, as they are also in Dicotyledons generally the adhesion, in this case, may be regarded as accidental, though it is very characteristic of the fruit of grasses. Cutting the grain open, we find the embryo near the base occupying about one-fourth or one-fifth of its contents, the rest of the seed being filled with a starchy albumen. 8. The structure of this embryo we must endeavour to understand, though in order to make it clearly out very C FIG. 42. Longitudinal sections, cut at right angles, of the Embryo of Wheat, showing the cotyledon c, the plumule pl, and the root-buds, r. careful sections must be made through it lengthwise. The accompanying cut will supply a good idea. of the arrangement of its parts. We do not find the first leaves of the embryo opposite to each other, forming a pair of cotyledons, as in the Bean and other Dicotyledons, but they are alternate; the outermost only being regarded as a seedleaf or cotyledon. Those which it sheaths belong to the plumule. The cotyledon being single, the embryo of Wheat is called monocotyledonous. The lower part of the embryo is the radicle. This never directly elongates in germination, but the internal, rudimentary root-buds, r, burst through it and develope into the root-fibres of the plant. The process of germination is similar to that of Dicotyledons, with this difference in regard to the origin of the root: the sheathing portion of the cotyledon is protruded from the seed, and embraces the base of the plumule, which ultimately developes into a stem. Now a structure similar to that of Wheat we find in the seeds of other corn-plants. In Rice the grain (fruit) presents |