336 



♦ KNOWLEDGE 



[JoNE 8, 18i-3 



long as tlip corresponding stage of tlio nioon'!i, and the 1 2 

 luillioa years of earth history correspond to about two 

 million years of nioon life. Ten million years ago, then, 

 the moon was in the same stage of planetary life that the 

 earth is now passing through. But those ten millions of 

 years of uioon-life correspond to sixty millions of years 

 of earth-life. Wherefore, on the very moderate assump- 

 tion I have made as to the time which has elapsed since 

 earth and moon were both young, sixty millions of years 

 would have to elapse before the earth would have reached 

 the stage of life through which the moon is now passing. — 

 Neiccuslle Weeklij Chronicle. 



A NATURALIST'S YEAR. 



By Grant Allen. 



XIV.— AMONG THE GRASSE.S. 



^ J1HE meadows are now all out in full blossom, and the 

 L various sedges, grasses, and plantains, which make 

 up the larger part of their greensward, are at this moment 

 in the busiest epoch of their existence, universally engaged 

 in getting themselves fertilised by the friendly interven- 

 tion of the unconscious wind. Pick any one of them that 

 you choose for examination, and you will find that, widely 

 as these meadow plants differ from one another in origin 

 and in underlying botanical structure, they are all closely 

 similar in external and adaptive characteristics. By the 

 very necessity of the situation they are almost universally 

 wind-fertilised, and they have undergone a certain number 

 of modifications in a single direction, in order to fit them 

 for this particular niche in Nature. Insect fertilised 

 plants may have their flowers buried among the foliage 

 or pressed close to the ground, provided only they are 

 conspicuous enough to attract the eyes of passing 

 insects ; but wind-fertilised blossoms must raise their 

 heads high above the neighbouring foliage, so as to 

 have free access to the breezes of heaven ; and so all 

 these grasses, sedges, and plantains have tall tufted flowers 

 usually hanging loose in graceful, plume-like panicles, so as 

 to be easily moved by every gentle breath of wind. Then, 

 again, the stamens themselves hang far out of the enclosing 

 scales or glumes, on long thread-like filaments, and quiver 

 like aspen leaves before the faintest flutter of the air, so as 

 to shed their pollen readily and instantaneously, wherever 

 the wind is ready to carry it. Finally, the stigmas, or sen- 

 sitive surfaces of the ovary, also protrude bodily from their 

 coverings, and are split up rnto innumerable little feathery 

 branches, so as to catch whatever pollen may chance to be 

 wafted their way. If you look closely at the surface of a 

 meadow waving in the wind, you will see that it is all one 

 mass of tiny purple bloom, shivering tremulously before the 

 breeze, and scattering little showers of light pollen with 

 every movement of the pendulous heads and stems. 



Of course, plants of such a sort can only succeed under 

 a combination of two diverse conditions. In the first place, 

 they must grow in open, unimpeded places, where the breeze 

 can get at them freely, and the pollen can be carried before 

 it without let or hindrance. In the second place they must 

 grow together in large masses — must be gregarious in habit 

 — or else the pollen would most probably get wasted in 

 traversing the distance between one plant of the species 

 and another. Among all the herbs which have adapted 

 themselves to this peculiar conjunction of circumstances 

 there are none more successful than the grasses. Indeed, 

 most careless observers imagine that the sward of a meadow 

 or pasture is almost entirely made up of grasses ; and 



though this is very far from being the case (for at least one- 

 half the plants in it are larger-leaved species, such as clovers, 

 sorrels, and buttercups) yet the grasses certainly occur in 

 such large numbers, and so overtop the other weeds around 

 them, as to give the general character and tone to the low- 

 land flora of temperate countries like our own England. If 

 we glance for a moment at their constitution and nature, 

 wo shall be getting an insight into one of the most dominant 

 plant families in the whole creation. 



The simplest grass you can possibly take, in order to 

 understand the flowering system of the entire group, is that 

 known to farmers and children as rye-grass, and technically 

 described as LoHitni jiereiuw. It is a common roadside 

 weed in every part of Britain, with a tall, stifT, blossoming 

 stem, and a number of spiky flower-heads stuck on alter- 

 nately upon either side of the stalk, which is deeply in- 

 dented first on the right and then on the left, in order to 

 make room for them. Each such flower-head is technically 

 known as a spikelet, and it consists usually of some eight 

 or ten tiny fiowers, closely crowded together along the edge 

 of a central stem or axis. The best way to understand the 

 flowers is to hiegin with the lowest spikelet of the head, and 

 pull ofi" the fiowers one by one, dissecting them with a pin 

 as you go. The outer piece of all is an empty bract, 

 which nearly encloses the whole spikelet, and keeps out 

 unwelcome visitors, such as pollen-eating flies, weevils, and 

 caterpillars. It is very stout, and thickly-ribbed, so as to 

 serve its purpose of defensive armour. Next comes the lowest 

 flower of the group, a degraded lily, so very degenerate 

 that you would hardly guess at first sight the real relations 

 of its parts. It is enclosed between two green organs, 

 kno^vn as glumes, which are, in fact, the representatives of 

 the three original calyx pieces. One of these, the outer, 

 or " flowering glume," is large and convex, rolled round 

 the edge of the other, which is thin and flat. The flat 

 " inner glume," or " palea," has two green ribs near its 

 middle, thus showing that it is really two calyx-pieces 

 rolled into one. Removing these with your pin, very 

 carefully, you come upon the actual floral organs. But 

 where are the three petals 1 Ah ! to find them you have 

 to look very close indeed, and I won't guarantee that, 

 without a lens, you will be able to see them at all. Still, 

 if you have good eyes, you may possibly be able to make 

 out two tiny white scales, very thin and almost transparent, 

 between the outer glume and the base of the ovary. 

 Those are the last faint relics of the two outer 

 petals. As to the inner one, it has got crushed out of 

 existence altogether by the mutual pressure of the florets 

 against one another on the side turned towards the axis. 

 The plant, in fact, had no further need for petals, since it 

 Joes not now wish to attract insects ; and therefore the 

 real wonder is, not that one of them has disappeared, but 

 that two of them should remain at all, even in the most 

 rudimentary state, as evidences of their former presence. 

 In many small grasses they have died out altogether ; it is 

 only in the larger kinds that any trace of them still exists. 

 The stamens, on the other hand, being equally important 

 to the plant under any circumstances, are there in full 

 force — three of them, as in the lilies, but hanging out at 

 the end of their long-waving filaments. Lastly, the ovary 

 consists of a single cell, containing one rich seed, the grain 

 which has given all the grasses their marked superiority in 

 the struggle for existence. The remaining florets on the 

 spikelet are each a repetition of this first pattern one ; and 

 the remaining spikelets of the head are similarly made up 

 of an external enclosing bract and eight or ten small 

 packed florets. 



That, as I said, is the simplest general plan upon wliich 

 all the grass-flowers are built up ; but in most of them this 



