April 20, 1883.] 



KNOWLEDGE 



231 



A NATURALIST'S YEAR. 



By Grant Allen. 



XL— MABSH MAKIGOLD. 



JF any promising young resthete wants to introduce a 

 pleasing variation on the monotony of sunflowers and 

 daflbdils, he cannot do better than set up an original 

 fashion of his own for admiring our common beautiful 

 bright English marsh-marigolds. Except, pei-haps, the 

 globe-flower and the greater spearwort, no British blossom 

 can vie with them in the brilliancy of their golden colour- 

 ing ; and when the)- grow naturally among their own 

 broad, heart-shaped, glossy-green foliage on a patch of 

 spongy ground beside some little brooklet, they are as 

 beautiful objects as even the most fastidious of decorative 

 artists could wish to feast his eyes upon. At first sight, 

 the marsh-marigold looks like a very big yellow buttercup, 

 only richer in hue and more luxuriant in its marshy 

 growth : and so it really is in all fundamental essentials ; 

 but it difl'ers more widely from the true buttercup type in 

 many important points of structure than most unbotanical 

 observers would easily imagine at a first rough glance. I 

 palled to pieces a common meadow-buttercup and examined 

 its structure here one day a twelvemonth since ; let us pull 

 to pieces a marsh- marigold in like fashion together this 

 morning, and see what are the noteworthy points of agree- 

 ment and difference between the two types. 



The first thing that strikes one about the marsh-marigold 

 is the fact that, in spite of its brilliant golden colour, it has 

 really no petals. This is certainly rather a surprise to the 

 loTer of flowers who, for the fir^t time, examines closely 

 one of these lovely April blossoms: for the sepals or calyx- 

 pieces are so large, so broadly expanded, so brightly co- 

 loured, and so exactly like the buttercup petals in hue and 

 shape, that it is almost impossible at first to believe they 

 do not really belong to the corolla. You might almost, for 

 a moment, imagine that the true sepals were very short- 

 lived, as in the poppy and the yellow eschscholtzias of our 

 flower-gardens, and that they had fallen ofl from the open 

 blossoms at an extremely early stage, leaving the yellow 

 petals as the apparent outer whorl of the entire flower. 

 But when you come to examine an unopened bud upon the 

 same plant, you will see at once that this explanation is 

 not the true one, and that the large coloured petal- like 

 organs are, in fact, the sepals, and no other part what- 

 soever. You will find that in the youngest buds of all 

 ttey are green and quite external : and that, as they grow 

 older, they get gradually larger and yellower, until at last 

 they expand into the perfect similitude of five big, bright 

 golden petals. It is quite clear, then, that for some good 

 reason of its own, the plant lias so specialised the outermost 

 •r true calyx-wliorl of flower-leaves, as to perform the 

 function usually performed by the second or coroUine row 

 for other blossoms. 



When we examine the intermediate stages, or the 

 analogovis cases elsewhere, the reason for this curious — I 

 had almost said this wanton — proceeding, becomes fairly 

 obvious. Even in the buttercup, the calyx-pieces are 

 faintly coloured, though they serve no attractive purpose 

 in the economy of the plant, being rather provided with a 

 hairy outer coat, so as to prevent thie\ing ants from 

 creeping up to steal the honey. Inside this protective 

 whorl comes the corolla of five golden petals, each with a 

 nectary at its base, to attract the fertilising bee. But most 

 buttercups are rather cup-shaped ; and in many cup shaped 

 flowers it happens that from certain , points of view the 

 calyx becomes really far more conspicuous than the corolla. 

 Wherever this is the case, it is usual to find the calyx- 



pieces at least as brightly coloured as the petals ; for, under 

 such circumstances, any heightening of the faint colouration 

 almost always displayed by the calyx would prove beneficial 

 to the species by aiding in the attractiveness of its general 

 display, and would therefore be favoured by natural selec- 

 tion. For example, in this very same buttercup family 

 there are three or four developed tribes, such as the monks- 

 hoods, the larkspurs, and the Christmas roses, in all of 

 which the large cup-shaped, or bell shaped, or helmet-shaped 

 sepals are more exposed to view than the small honey- 

 bearing petals ; and in all, the sepals accordingly, rather 

 than the petals, form the attractive advertising organ. The 

 plants, in short, are good advertisers ; they insert their 

 colour advertisements in the best available medium. 



Now, we have a rare wild plant in some parts of 

 England and Wales — the globe flower — which to some 

 extent stands half-way in this respect between the butter- 

 cup and the marth-marigold. It has from ten to fifteen 

 large concave golden sepals outside each blossom, and 

 these form, as in the marsh-marigold, the real alluring 

 surface. But inside them it still retains a set of small, 

 long, narrow yellow petals, dwarfed almost out of recogni- 

 tion, and quite flat, because, though they secrete honey, 

 they no longer take any part in the real function of attract- 

 ing insects from a distance. To a certain extent, there- 

 fore, I said, we may regard the globe-flower as representing 

 a middle stage between the buttercup and the marsh- 

 marigold. Still, we must not consider that our own species 

 is really an exactly intermediate form, because, while the 

 buttercup has five sepals and petals, and while the marsh- 

 marigold has also five sepal.«, the sepals and petals of the 

 English globe-flower usually number from ten to fifteen 

 each. There are, however, foreign globe-flowers with only 

 five of either kind, and one of these may perhaps be, in 

 fact, a genuine link between the two tribes — the ancestral 

 and the derivative. 



From some such ancestor as this, then — a buttercup 

 with five large, bright golden sepals, and five tiny, dwarfed 

 petals — our English marsh-marigold is probably descended. 

 But it has acquired a peculiarity of its own which has 

 enabled it to dispense with its rudimentary petals, and so 

 to effect a complete saving of the material which would 

 otherwise have gone to make them up ; for it has taken to 

 secreting the honey in the very centre of the flower, on the 

 young seed-vessels themselves, a habit which, of course, 

 renders the little narrow petals quite unnecessary. Ac- 

 cordingl)-, through the working of what is called the law of 

 parsimony (by which all useless parts grow gradually 

 obsolete), it has now lost them altogether, retaining only 

 the very large and petal like yellow calyx-pieces. 



At the same time our plant has undergone another 

 important structural change, which it also shares with the 

 globe-flowers and with all the higher buttercup kinds, such 

 as the monkshood and the columbine. In the centre of 

 the common meadow buttercup, you will recollect, there 

 are several rows of small, solitary, one-seeded carpels, all 

 mixed together into a very irregular unsymmetrical crowd. 

 This was apparently the earliest condition of the pistil (or 

 unripe fruit) in all primitive plants ; certainly it is the 

 condition of the pistil in all the simplest and most aboriginal 

 surviving examples. But as plants develop better means 

 of cross-fertilisation by means of insects, and rise higher 

 in the scale of organisation, it pays them better to 

 lessen the number of such carpels, and to put several 

 seeds in each of them instead of one only. In other 

 words, those which happen from time to time to 

 have the fewest carpels, and the most seeds in each 

 carpel, survive and thrive best, while those which 

 reverse this rule run the poorest chance in the struggle 



