Peaflowers appear to be especially constructed to make use of the visits of large insects, such as bees, for purposes of cross-fertilisation. In the centre of the flower, around the base, of the pistil, a sugary fluid is secreted. A bee in search of this alights on the keel, and in struggling to reach this nectar it depresses the point of the keel; the anthers and stigma immediately jump up, with the result that the pollen is dusted on the under part of its body-When the bee visits another flower the process recurs, with the result that the stigma is dusted with the pollen it brought with it. It will be readily preceived there is nothing in this to prevent the pollen of its own flower getting on the stigma. This really occurs, and effects fertilisation if no foreign pollen is present. Here comes in one of the provisions . to prevent self-fertilisation. Its own pollen acts very slowly, and if not given too long a start the much more rapid developing foreign pollen overtakes it, and fertilises the ovules. This selection of one pollen over another is called prepotency.
There is a small family, to which our Love creeper belongs, whose flowers at first sight resemble Peaflowers. But it is only a general resemblance; they are really not at all alike and the fruit is not a legume. They will be dealt with later.
It would be a natural conclusion that plants related to one another should have similar fruits, and conversely that similar fruits in two plants should indicate a close relationship, but this does not appear to be the case. Fruits of like structure do not indicate common descent. They are specialised developments to insure the effective dispersal of the seed; consequently any advantageous change in form of any member of a family may give it an advantage which will enable it to reproduce its kind more successfully than its less fortunate relatives. The same thing applies to leaves. Consequently very different leaves may be found in one family and similar leaves may be found in very different ones. Particular forms of fruit or leaves must not therefore be taken to mean relationship. The leaf of the Plane is very like a Maple. The fruit of the Blue Climbing Berry, which is closely allied to Pittos-porum, is similarly constructed to the fruit of the Blue Berry and Turquoise Berry, which are both Lilies. But although this similarity of fruit and leaf is not to be relied upon as indicating relationship, yet we find in some instances a peculiar form of leaf or fruit may be common to one family; further, it may be confined to the members of one family. This fact has led enterprising geologists to discover in certain leaf-impressions the presence of Oaks, Willows, Elms, and many other families in rock strata. It is certain that some of these conclusions are erroneous. This family, as already said, is a very large one. Some are small herbs; others tall trees. Some grow erect; others grow flat on the ground. Some have a copious foliage: others no leaves at all. Yet all conform to the same type of flower and fruit.
We have no room to draw attention to more than a few forms. In sandy spots, especially near the sea, the Running Postman is often found. The branches are slender and lie flat on the ground, bearing leaves with three flat broad leaflets. The flowers are rather large and bright crimson, rarely white, forming conspicuous objects. The lower nine stamens are united for some distance, and the upper one free. The pod is rather long, cylindric, and many-seeded.
Native Gorse is an erect, much-branched shrub. Its leaves are very sharp, but vary greatly in breadth. Some-times they are very narrow, like spines; at others they are broad, but always sharply pointed. The flowers are small, yellow, and in axillary bunches. The pod is small, flat, and triangular. To the same genus as this belongs Bitterleaf, or, as it is often called, Native Hop. It differs in the leaves being broad, blunt, with conspicuous netted veins and very bitter taste. The name Native Hop is bad, not only because it is no relation to the Hop, but because the name is also given to a small tree whose fruits have a fanciful resemblance to those of Hop.
Prickly Beauty. ( Pultenaca juniperina, Lab. [See p. 25
Clovertree is a tall shrub, with trifoliate, cloverlike leaves and pale-yellow flowers in loose clusters.
Native Indigo is a true Indigo. It has leaves with numerous flat leaflets, long slender branches, and clusters of pretty dark-pink flowers.
In Tasmania we have a few Peaflowers whose leaves are reduced to little or nothing. The commonest is a wiry little Sphaerolobium, seldom more than a foot high, with numerous small yellow flowers arranged singly along the branches. It is found in grassy places. Another leafless plant found on poor mudstone hills is Bossiaea riparia. It is a little shrub, and to make up for the absence of leaves the branches are flat and broad. Unfortunately, these last two have no popular names.
Plants are not passive objects responding indifferently to their surroundings. They are endowed with life just as well as animals. If they differ it is only in detail, not in principle. Animals and plants are made separate kingdoms for our convenience, and not from any clear distinction. They are but one series of beings, differing greatly when the extremes are considered, but absolutely continuous where they meet.
Plants do not see nor hear, nor is there any reason to think they feel in the sense that they are conscious of a disturbance. Nor are lower animals possessed of these powers. But plants have the ordinary functions of living beings, and also special senses of great acuteness. Because we do not find in them the senses we possess, we do not at first sight credit them with any. Yet plants are sensitive to gravity, light, heat; and contact, according to their kind, and that to a degree of extreme delicacy.
Every plant has a constitution of its own, an individuality. It is capable of responding to outside influences, but only along certain restricted lines. It can only respond as far as the peculiar composition of its substance will permit. This is generally called inherited disposition. But a being cannot inherit a history. It can only receive substance, and were its substance the exact counterpart of that of perfectly similar parents, and its surroundings were exactly the same, then the young would be just a repetition. But the factors are never the same therefore we have infinity of variation. An ovule is not a new thing; it is simply the constricting off of a particle of substance from the parent. It becomes complicated by the blending with it of the contents of a pollen grain derived generally from a slightly different plant. It then grows into an individual, but though independent, it is simply a continuation of the life of the parents with their functions and possibilities. Therefore, when we speak of inherited qualities, we simply mean the substance of which the new plant is formed was not changed in character in being separated from its ancestor. We should consider it extraordinary if it was.