One of the wood-rushes still shows remarkable approximation to the conditions of insect-fertilized flowers, and two of them are visited, now and then, by insects.
It seems probable that the little petals, now sere and translucent, were once soft in texture and lovely in hue.
In those days insects may have "visited around ' among the rushes numerously and often.
But the petals and sepals which the flowers wear nowadays are ineffective for display or allurement, - and seem to be produced merely for "old sake's sake".
The rush flowers are very dependent upon their present messenger, the wind, for the pistils, in most of the species, ripen first. So they are ready for pollen before the home-grown pollen is ready for them, and must use the life-giving dust which is blown to them from older flowers.
The ripe pollen is smooth and powdery, so that it may readily be detached by the wind and borne away, but the anthers do not sway at the lips of slender filaments, as they do in the thorough - going wind - fertilized blossoms of the grasses.
The seeds of the wood-rushes are matured by midsummer.
Those of the water-rushes are not ripe till August or September.
Both sorts are borne in dry capsules, which split into three valves, setting the seeds free.
But the wood-rush capsules have just three seeds apiece, while those of the water-rushes contain a large number.
It is not uncommon for water-loving plants to put a relatively enormous progeny forth upon the world, for seedlings which cannot thrive unless they keep their feet wet are peculiarly the victims of chance and change. Many will begin life in dry ground, where they will speedily wither away because they lack moisture; and even those which have the luck to fall into water or mud find life full of uncertainties. The rivers which they love shift their courses, the brooks and ponds dry up, the swamps are drained.
Wood-rush seeds can settle and thrive in any piece of open wood- or meadow-land.
But in regulating the affairs of the water-rushes, cat-tail flags and pickerel-weed, Nature provides beforehand for an altogether probable slaughter of the innocents.
Under the microscope the seeds borne by several of the water-rushes show a delicate cross-bar pattern in high relief, and some are tipped with a queer little horn (Fig. 50).
In latter summer the cells which go to make up these cross-bars and horns become converted into mucilage. At first this mucilage is dry and hard, but it can absorb a great quantity of water, and as it does so it becomes soft and swells astonishingly. The first heavy autumnal rains give it an opportunity to exercise its capabilities.
Fig. 50. - Rush-seeds.
1, Juncus Greenii; 2, Juncus tenuis.
In the moist atmosphere the ridges and horns dissolve, and the seeds become embedded in a mass of viscid jelly. The mass swells up, forces its way through the slits in the now opened capsule, and carries the seeds out with it. By exposure to air and sun the mucilage becomes brittle and powdery. Then the seeds are readily detached from it and carried off by autumn gales to seek their fortunes.
One would think that this method of seed distribution might be unique. But it has been adopted also by a little flower called "yellow-eyed-grass" (Xyris flexuosa), which often lives as neighbor to the water-rushes, and so must adapt itself to similar conditions. Yet the cousinship be-tween these two plant families is of that remote degree which in human relations "counts for nothing" north of Mason and Dixon's line.
The seeds of both water-rushes and yellow-eyed-grass are small and light, so that they can be blown far afield in quest of an abiding place, and they are long and narrow, and hence expose a large proportionate surface to the wind.
The ripe seed vessels of all the rushes are surrounded by the dry petals and sepals of the little flower, and by the same token we can always distinguish a rush from the wind's other fosterlings afield (Fig. 51).
Fig. 51. - Some New England sedges.
1, Eleocharis tuberculosa, "spike-rush"; 2, Eriphorum alpinum, "cotton-grass"; 3, Carex grisea; 4, Eriphorum polystachyon, "cotton-grass"; 5, Carex tribuloides; 6, Carex crinita; 7, Carex stipata; 8, Scirpus sylvati-cus, the true "bul-rush" (in fruit); 9, Scirpus sylvaticus (in flower); 10, Carex lupulina.
The sedges can readily be recognized and known from the grasses, their next of kin, for grass-stems are usually hollow and always round, while those of the sedges are solid, and, at least toward their tips, triangular. Moreover, sedges grow in tussocks, and grasses form a close, continuous mat upon the ground.
The bases of sedge-leaves are not merely wrapped about the stem, after the fashion of the grasses, but they form seamless, tubular sheaths, which invest it closely.
In old England all sedges were included under the name of "shear-grass," a term applied to them on account of the sharp or scissor-like edges of their narrow leaves.
The same characteristic got them the name by which we know them, for "sedge" and "saw" are both derived from an old Teutonic word, which means "to cut".
The leaves are disposed along the stem in what is known as the "three-ranked arrangement," the fourth, as one counts upward, being directly above the first and the fifth above the second, so that if one should draw a line through the bases of the leaves it would intersect three in the course of one complete spiral turn.