Fig. 96.—Daffodil flower,
cut down the middle. (× ⅔.)
It will be noticed that the parts of the flower are in threes. There are six united perianth leaves (three inner and three outer), six stamens (also in two series), and three united carpels. This is very common—though by no means universal—in monocotyledons.
All the plants of the lily family—including the tulips, the true lilies, lily of the valley, asparagus, onion, etc.—agree in being monocotyledons, and in their flowers having a conspicuous perianth (for attracting insects) and six stamens, and in the ovary being above the insertion of the perianth.
The snowdrop family.—Plants of this family are very similar to those of the lily family; in fact in only one respect can any sharp line of demarcation be drawn between the two groups; in the snowdrop and its relatives the other parts of the flower stand upon the ovary ([Fig. 96]). The flowers of some plants of the family, e.g. the daffodil, possess a tubular outgrowth of the perianth, which is called a corona. It is often mistaken for a corolla.
26. THE ARUM LILY.
1. The cuckoo-pint.—Examine the habit of the plant, and then cut open the “flower.” You will probably find a number of small flies inside. Examine the central rod and make out the stamens and pistils on it. Which ripen first?
The arum “lily,” with its humble relative the cuckoo-pint ([Fig. 97]), merits special mention; for, in the first place, it is not a lily at all, and secondly, it furnishes an extremely interesting example of pistils coming to maturity before anthers, which is rather rare.
What is generally called the “flower” of the cuckoo-pint, or “lords and ladies,” consists of a big curled leaf with a purple rod sticking up in the middle. Near the bottom of the rod, but hidden from sight by the lower part of the leaf, the true flowers arise. The chamber containing them is shut in by a series of stiffish hairs which point downwards. Below the hairs the rod supports a series of anthers and, near the bottom of the chamber, several pistils. On cutting open the chamber one nearly always finds a number of small flies, covered with pollen, which they have brought from another arum. The flies get in easily enough, but once in they are prisoners, for the down-pointing hairs prevent them from getting out again. The pistils near the bottom of the rod ripen, and are fertilised by the pollen the flies have brought. After a time the anthers above ripen and shed their welcome pollen on the hungry captives. Soon after this the hairs at the top of the chamber shrivel up, and the flies, once more covered with pollen, are at liberty to return to the outer world and, untaught by experience, to repeat the experiment on another “flower.”
