Nov. 25, 1881.] 



♦ KNOWLEDGE 



65 



',></>>:H!>. I 



.-VjL V"* AN ILLU&TRATED 



; ^ MAGJ^ZI'NE orSGIENCE 



j, ,, PLAINLY3!f ORJED -£XACTLY|ESCRIBED 



LOXDOX: FRIDAY, XOVEMBER 25, 1881. 



CONTENTS. 



The Oriein of Bntteronps 63 



Solids. Liquids, and Gases.— Fart U. 



Bt W. Mattieu Williams 66 



Geriilsofl)i<>-a«e and Death. Bt Dr. 



Andrew Wilson, F.B.S.E .' 67 



The Ijiws of Probability 68 



IntelliK.'nce in Animals— (rai<.(ra/«i/) 69 

 Illusions. Bv Thomas Foster— (///lu- 



trattd) ...'. 70 



Reviews :— .\uthor3 and PnbUshers 73 

 Correspondence : — To Our Readers, 

 4c. —The Missing Link— The Sun's 

 Heat— The Suns Heat (AbflracI) 

 —Star Names :— Comets' Tails- 

 Practical Work with the Telescope : 



F.KGE 



Map of Eastern .Skies— Celestial 

 Objects — Are Women Inferior to 

 Men? {Abstract)— iipeeA of Ame. 

 rican Ice-Yachts— Are Men's iloads 



Smaller than of Yore? Ac 73 



Queries 8i) 



EepUes to Queries.. 80 



Anniversory Meeting of the Bir- 

 mingham' and Midland Institute 

 Union of Teachers and Students. 



Bv W. M!>t lieu Williams 81 



Onr Mathematical Column SI 



Our Chess Column .. S2 



Our Whist Column »3 



Answers to Correspondents S4 



THE ORIGIN OF BUTTERCUPS. 



By Gkaxt Alien'. 



HERE, in my hand, I hold a solitary little golden 

 buttercup, picked this morning in an autumn meadow, 

 but still as bright and sturdy as though it had grown up 

 in warmer days beneath the sunny skies of June. Common 

 and familiar as it is, the buttercup is yet a very interesting 

 flower from the point of view of its origin and evolution. 

 Not that it is a highly-evolved or very singular blossom, 

 with a long and intricate liistory at its back, like some of 

 the orchids and snapdragons, whose complexity almost 

 defies explanation ; on the contrary, the importance of the 

 buttercup in the eyes of the historical botanist is mainly 

 due to the extreme simplicity of its typical arrangement. 

 It is a very early type of plant, which has scarcely under- 

 gone any alteration from the form it must have acquired 

 already many millions of years ago. There are other 

 flowers of the same famOj', such as the larkspur, the colum- 

 bine, and the monkshood, which still bear obvious traces of 

 being derived from an ancestor exactly like the buttercup, 

 but which have diverged widely from the original stock in 

 their curious irregular flowers, sometimes spurred, some- 

 times hooded, and sometimes so altered from the primitive 

 radial shape as to be scarcely recognisable. What makes 

 our buttercup so interesting, on the other hand, is the fact 

 that it represents an early stage in the history of these 

 more highly-developed forms. In order to understand 

 them we must first understand it. This buttercup, in 

 sliort, is one of the most central members of the family to 

 which it belongs ; while some of its congeners have diverged 

 in one direction and some in another, it has still kept 

 unaltered for us the primitive lineaments of the common 

 ancestor from which all alike have ultimately sprung. 



Buttercups, as everybody knows, are tall meadow weeds, 

 and the one which I hold in my hand belongs to the 

 tallest species of all, which we know par exceUenre as the 

 buttercup ; for we have in England alone no less than 

 some sixteen representatives of the entire genus. Let us 

 look a little closely into its structuj-e, and see what hints 

 we .can gather from its existing shape as to its past history 

 and evolution. 



First of all there are the leaves. These, one notices at 



once, are raised on long stalks, and deeply di\-ided into 

 several segments. Sometimes there are only three divisions 

 to each leaf, sometimes five, and sometimes seven ; the 

 reason why thej- thus run in uneven numljers being, of 

 course, that there is always a single terminal leaflet together, 

 with one, two, or three lateral leaflets or either side of it. 

 Again, each of these segments is itself further di\ ided into 

 three toothed lobes. Now, such a complex leaf as this 

 shows by its very nature that it must be the product of 

 considerable previous development. All very early 

 leaves are quite simple and rounded ; it is only by slow 

 steps that a leaf thus gets Ijroken up into many clividcd 

 segments. In this re.spect, then, the meadow buttercup 

 cannot be regarded as the simplest member of its class. 

 There are some other buttercups, such as the ivy-leaved 

 crowfoot, which creeps along the ml of ditches, or the 

 lesser celandine, which springs in t ^ meadows in early 

 April, whose leaves are entire ani. undivided. In the 

 lesser celandine they are almost cirt !ar, and in the ivy- 

 leaved crowfoot they are slightly anj,ular ; but both these 

 plants, ha\-ing pie. ty of room to spread in the unoccupied 

 fields of spring or the unappropriated ditches, have never 

 felt the necessity for subdivision into mmute segments. 

 They have free access to the air and the sunlight, and so 

 they can assimilate to their hearts' content the carbon of 

 which their tissues are built up. It is otherwise, however, 

 when similar plants push out into new situations, less 

 fully supplied with carbonic acid or with sunshine. For 

 example, there is the water-crowfoot, a mere divergent 

 variety of the i%y-leaved species, which has taken to grow- 

 ing in ponds or rivers. Here it cannot obtain the material-s 

 for gi'owth so readily as on its native mud-banks ; and it 

 has been compelled, accordingly, to split up its submerged 

 leaves into long, thin, hair-like filaments ; but when it 

 reaches the surface, its foliage spreads out once more 

 into the broad ancestral blades of the ivy-leaved crow- 

 foot. It is just the same with the true buttercups. 

 They have taken to growing in the open meadows, 

 where the competition for vegetable food-stufts is keen, 

 and the struggle for existence very bitter. Hence they 

 have been compelled to di^•ide their leaves into many 

 finger-like segments ; and only those which have succeeded 

 in doing so have managed to hold their own in the struggle, 

 and so to hand down tlieir peculiarities to futm-e gener.i- 

 tions. As a rule, just in proportion as vegetation is thick 

 and matted, do the plants of which it is composed tend to 

 develope minutely divided and attenuated foliage. 



It is the flower, however, that most people think of as 

 the essential part of a buttercup, and it is by means of the 

 flower that all the higher plants are usually classified. 

 Now, the blossom of the buttercup is almost an ideally 

 simple typical specimen. It consists of three parts or 

 series of organs, from -n-ithin outward. First comes a little 

 central boss or cushion, supporting several carpels c^r 

 unripe fruitlets. Each of these carpels contains a single 

 embryo seed. Outside these comes a row of many stamens, 

 which are the organs for producing the yellow dust which 

 we call pollen. Now, no cai-pel can mature into a fruit 

 containing ripe seed until it has been imj^regnated bj' 

 pollen from a stamen, and these two sets of organs are, 

 therefore, the only really essential parts of the whole 

 flower. But in common language, what we mean by a 

 flower is not these little central knolis and tassels, but 

 rather the bright-coloured petals outside, which in the 

 buttercup are five in number and golden yellow in colour. 

 What, then, is the use to the plant of these expanded and 

 very strikingly-coloured organs 1 



A flower is at bottom merely a device for producing seed. 

 But in order that the seed may prove capable of germinat- 



