Field and Woodland Plants. William S. Furneaux
no stamens or no pistil. If such possess stamens and no pistil, they are called staminate or male flowers; and if pistil and no stamens, pistillate or female flowers. These two kinds are sometimes borne on the same plant, when they are said to be monœcious; but often on separate plants (diœcious), as in some of the Nettleworts and the Willow Tree. Spikes of unisexual flowers, such as are common among our forest trees, are called catkins.
The Fruit and Seed
Dehiscent Fruits
1. Pod. 2. Siliqua. 3. Silicula. 4. Follicles(cluster of three). 5. Capsule splitting longitudinally. 6. Capsule splitting transversely. 7. Capsule splitting by pores.
After the ovules have been impregnated by the pollen they develop into seeds, each of which consists of or contains an embryo plant; and, at the same time, the ovary itself enlarges, changing its character more or less, till it becomes a ripened fruit.
Fruits vary very considerably in their general characters, but may be divided into two main groups—those that split when ripe (dehiscent fruits) and those which do not split (indehiscent fruits).
The principal forms of dehiscent fruits are:—
1. The pod or legume, which splits into two valves, with placenta on one side.
2. The siliqua, a long, narrow fruit that splits into two valves which separate from a membrane with placenta on both sides.
3. The silicula, of the same nature as the siliqua, but about as broad as it is long.
4. The follicle, which splits on one side only, through the placenta.
5. All other fruits that split are termed capsules. Some of these split longitudinally, some transversely, and others by forming pores for the escape of the seeds.
The chief kinds of indehiscent fruits are:—
1. The drupe or stone-fruit, which consists of a hard stone surrounded by a fleshy covering, as the plum and the cherry.
2. The berry, which is soft and fleshy, and contains several seeds, like the currant and the grape.
3. The nut or achene—a fruit with hard and dry walls, as the filbert and the acorn.
4. The samara or winged fruit, like that of the sycamore.
Various modifications of these indehiscent fruits are to be met with; thus, the blackberry is not really a berry, but a cluster of little drupes formed from a single pistil of many carpels. A berry, too, may be made up of many parts, as is the case with the orange. The apple and similar fruits consist of a core (the true fruit) surrounded by a fleshy mass that is produced from the receptacle of the flower; and the strawberry is a succulent, enlarged receptacle of the flower, with a number of little achenes (the true fruits) on its surface.
The seed, as we have already observed, is the embryo plant. It consists of one or more seed-leaves or cotyledons, a radicle or young root, and a plumule or young bud. In many cases the skin of the seed encloses nothing more than the three parts of the embryo, as named above; but it sometimes contains, in addition, a quantity of nutrient matter in the form of albumen, starch, oil, gum, or other substance.
Classification of Flowering Plants
Our flowering plants are divided into two main groups, the dicotyledons and the monocotyledons. These terms suggest that the division is based on the nature of the seed, which is really the case, but the groups are characterised by differences in other parts. Thus, the plants which produce seeds with two cotyledons may be known by the nature of the stem, which consists of a central pith, surrounded by wood arranged in one or more rings, and the whole enclosed in an outer epidermis or in a bark. These plants also bear leaves with netted veins, and the parts of the flower are usually in whorls of four or five or multiples of four or five. Those plants whose seeds have only one cotyledon may be known by the absence of a central pith and true bark in the stem, while the wood is arranged in scattered bundles instead of in a ring or rings. They have also, generally, leaves with parallel veins; and the parts of the flower are usually in threes or multiples of three. The following table shows these features at a glance:—
| Dicotyledons | Monocotyledons |
|---|---|
| Embryo with two cotyledons. | Embryo with one cotyledon. |
| Stem with central pith, wood in rings or rings, and bark. | Stem with no central pith, no true bark, and wood not in rings. |
| Leaves with netted veins. | Leaves with parallel veins. |
| Parts of flower usually in fours or fives. | Parts of flower arranged in threes or multiples of three. |
These two great divisions or classes are split up into sub-classes, each embracing a large number of plants with common characters; and the sub-classes are again divided into orders, and the orders into genera.
The student should always endeavour to determine the order to which any flower he finds belongs; and, if possible, the genus and the species. It is certainly a pleasure to be able to call flowers by their names, but at the same time it must be remembered that a vast deal of pleasure may be gained by the study of flowers—their peculiar structure, habits and habitats—even though their names are unknown; and the student who has learnt to recognise these characters, and to discover the relationships that exist between certain flowers of different species, is certainly much more fortunate than the one who knows abundance of names with only a meagre acquaintance with the flowers themselves.
Our table of classification gives the most important distinguishing characters of the classes, sub-classes, and orders, of a very large proportion of our wild flowers, and will enable the reader to determine the natural order of almost every one he sees. In order to show how this table is to be used we will take an imaginary example.
Let us suppose that we find a plant with a square stem; opposite, simple leaves with netted veins; flowers apparently in whorls, in the axils of the leaves; persistent calyx of five united sepals; a lipped corolla, of five united petals, two forming the lower, and three the upper lip; four stamens, attached to the corolla, two longer than the others; a superior, four-lobed ovary; and a fruit of four little nuts; then we proceed to determine the natural order to which it belongs as follows:—
The netted veins of the leaves, and the arrangement of the parts of the flower in whorls of four and five, show us at once that the plant is a dicotyledon. Then, the presence of both calyx and corolla enables us to decide that the plant belongs to Division I. of the dicotyledons—that it belongs to one of the orders 1 to 59. Noting, now, that the corolla is composed of united petals, we are enabled to fix its position in the subdivision I.B, among orders 37 to 59. Next, the superior ovary shows that it must be located in the group I.B 2—orders 44 to 59; and as the stamens are attached to the corolla, we see at once that it is not a member of order 44. Turning now to the Synopsis of the Natural Orders (p. 17), we find that the irregular flowers of this group of orders occur only in 51, 52, 53, 54, and 56. Finally, the square stem, opposite leaves, and character of the fruit, show us that the plant must belong to the order Labiatæ.