The Wild Arum.
Our next flower is the peculiar and interesting Wild Arum (Arum maculatum), of the order Araceæ, also known as Lords and Ladies, Cuckoo Pint, and Wake Robin. It is a very common flower of shady waysides, blooming during April and May. The plant is succulent, with a short, fleshy rhizome; and large, smooth, sagittate leaves that are often spotted with purple. The floral stalk is thick and fleshy, and supports numerous unisexual flowers which are clustered round a central axis or spadix that is prolonged above into a club-shaped appendage. The whole of the spadix is surrounded by a large bract or spathe which is contracted a little distance above its base. The portion of the spathe below the constriction encloses the flowers, and remains permanently closed as long as they are in bloom; but the upper part opens on one side, just before the flowers begin to mature, exposing the club of the spathe. The club is thick and fleshy, and coloured either dull purple, bright red, pink, or yellow. The pistillate flowers are clustered round the bottom of the spadix, and consist of a number of sessile ovaries. Above them is a ring of imperfect flowers consisting of styles only, and above these again is the cluster of staminate flowers, with some aborted stamens at the top. After fertilisation has taken place the spathe and the spadix soon wither away, and the ovaries develop into a cluster of large berry-like fruits, each containing a few seeds. These fruits, mounted on the summit of the lengthened, fleshy peduncle, are very conspicuous objects in the autumn hedgerows.
The contrivance by which cross-fertilisation is secured in these flowers is particularly interesting:—Numbers of little insects (midges) are attracted by the brightly coloured club, and, possibly, also by the fœtid odour of the flowers. These creep down the spadix, passing through the narrow neck into the closed compartment below. The neck is more or less obstructed by the upper, abortive, staminate flowers, which consist merely of a few whorls of bristles. Since, however, many of these bristles point downwards, they offer but little obstruction to insects as they enter; but prevent their escape. Thus, on cutting open the lower part of the spathe, we may frequently find quite a number of midges that have been imprisoned, their bodies covered with pollen that has probably been carried from another Arum previously visited. The pistillate flowers are mature first, and thus the imprisoned insects, creeping about in their cell during this early stage of the flower, are sure to bring pollen cells in contact with some of the ripened stigmas.
After the work of fertilisation has been accomplished, the anthers ripen, setting free abundance of pollen which now covers the bodies of the insects in the place of that which has been rubbed on to the stigmas. Then the abortive stamens, which prevented the escape of the insects, wither; and, at the same time, the neck of the spathe relaxes. Thus the prisoners are again set free, and possibly a large proportion of them enter another flower and repeat the process of cross-pollination.
The commonest of the early-flowering Grasses of the wayside is the Annual Meadow Grass (Poa annua)—a small tufted species, varying from a few inches to nearly a foot in height. It commences to flower in March, and remains in bloom till the end of the summer. It is represented on [Plate III].
[VIII]
MEADOWS, FIELDS AND PASTURES—SPRING
It is, of course, impossible to draw a hard and fast line between the flowers of spring and those of summer, for not only does each individual species vary in the time of its first appearance, according to the nature of the season, but many of the spring and summer flowers overlap in such a manner that it is difficult to decide which season has the greater claim to each one. In the present chapter, however, we shall include those flowers of our fields and meadows which usually commence to bloom before the beginning of June, even though they may continue to produce blossoms well into the summer.
One of the most conspicuous features of the meadows in spring is certainly the abundance of those bright yellow flowers known collectively as the Buttercups. But the name of Buttercup, standing alone, has no definite, scientific meaning, the name being applied to quite a number of flowers of the Ranunculus genus of the order Ranunculaceæ.