448 



• KNOWLEDGE • 



[Dec. 8, 1882. 



A NATURALIST'S YEAR. 



I.— At- TIM N BUDS. 

 1?V CiR-\HT AlLE.V. 



HOW full of promise for the coming season is this 

 little forked spray of hawtlioni, which 1 ha\e picked 

 from the hedgerow, already thickly covered with the buds 

 and leaves of next spring's foliage. In a certain sense, 

 indeed, one may fairly say that the naturalist's year bp^'ins 

 most truly in late autumn. It is then that many of the 

 animal life-cycles start on their appointed course ; it is 

 then that ne.xt year's seeds are sown, that next year's 

 leaves are rudely formed, tliat next year's eggs are buried 

 securely in the sheltering ground. Take, for example, the 

 ca>o of foliage and (lowers. To the casual observer, it 

 seems as though these most notable of all external objects, 

 which clothe the trees and the fields throughout the whole 

 summer, began their yearly course with the first return of 

 -Spring. In reality, however, many or most of them have 

 lived on in embryo forms from the preceding autumn. 

 This is the case even with annual seedlings ; for if you 

 cut open a seed, you will find that it consists of either one 

 or two seed-leaves (according as it belongs to one or other 

 of the two great flowering stocks), and these seed-leaves, 

 with their enclosed bud, are already perfect in the ripe 

 fruit, although they do not expand and develop their 

 feathery head until tlie spring comes with its warmth and 

 moisture to continue the arrested cycle of their growth. 

 With some precocious plants, indeed, the young seedlings 

 habitually sprout in great numbers during the autumn, 

 struggle on somehow through the cold season, and start 

 afresh with redoubled vigour in March or April. This is 

 espptially the case this year in England with the little 

 goosegrass or cleavers, which is now growing abundantly in 

 I'verj- hedgerow here, and is struggling among the brambles 

 and briars as if it meant to hold its own bravely till the 

 fro.sts are over. 



But what is true of the annuals to a certain extent is far 

 more deeply and universally true of perennials, like this bit 

 of Imwthorn. In all trees, for example, the buds which 

 represent the future branches for next year's growth arc 

 protluced and elalx>rated in the preceding autumn. As the 

 dea<l leaves fall ofl' in October, the living chlorophyll and 

 protoplasm which formed their active functional parts are 

 w ithdrawn into the permanent tissues of the tree ; and 

 their withdrawal, aided by variou.s internal chemical 

 • hanges, chi<-fly of the nature of oxidation, leaves the 

 ii:inor colouring matters of the foliage far more prominent 

 than before, and so gives rise to that glow of crimson and 

 gold which we commonly know as autumn tints. Then the 

 protoplasm and the other vital principles go in part to form 

 a reserve for next spring's growth, but in part also to pro- 

 dui-c the buds which are to live through the winter as 

 visible gymljols of the coming summer. Outside you see 

 the buda are enveloped in dry brown scales, which make 

 them very inconsjjicuous to the eyes of their enemies, who 

 would otherwiwf (|uickly devour these rising hopes of the 

 future stfoson. Clearly, such brown protective coverings 

 have Ijcen ac<juired by the buds through natural selection 

 of the best concealing hues, and by natural destruction or 

 eating off of all the greener or more noticeable buds. 

 Sometimes, however, a« in the familiar case of the horse 

 < Ue-itnut, the biidg themselves are so large and visible that 

 they cannot powibly be overlooked ; and this difference 

 everybody must have noticed for himself, giricewc very seldom 

 o>i«er\c the wint'-r buds on hawthorns or elms, but we 

 never fail to observe them on the horse-chestiiut. Under 

 th'v circunmtaticeK, the buds could never have escaped at 



all, if they did not possess some special and extra means of 

 protection ; and as a matter of fact we know that the 

 embryo liorse-chestnut leaves are protected by peculiarly 

 gummy and resinous scales, which etl'ectually ward off all 

 insect or animal foes. A\'herever we find very noticeable 

 winter buds, indeed, we almost always find some such 

 device for ensuring their survival, and in the few instances 

 where we cannot detect any such de^•ice,it is safer to conclude 

 that we have not yet fathomed all the tricks p.nd chances of 

 nature, than to conjecture hastily that no protective plan 

 at all exists for their benefit 'J'astes that are not nasty to 

 us, may be ^-ery nasty to many a grub or caterpillar ; leaves 

 that seem scentless to us, may be unpleasantly pungent to 

 the little smell-pits on the antennjeof nuvny a flying insect 

 hairs, and scales and glands that look utterly meaningless 

 to our clumsy eyes, may prove fearful and deterrent enough 

 to many a prowling beetle or wrevi'. Depend upon it, 

 there never was a worse bit of philosophy invented (which 

 is .saying a good deal) than that famous Greek phrase of 

 crystallised human vanity — " Man is the measure of all 

 things." 



The scales have another function to perform, however, 

 besides that of keeping off unwelcome visitors from the 

 young loaves. They act as great-coats or cloaks to cover 

 the dormant living germs from the cold of winter. Every- 

 l)ody knows that frost kills plants ; and everybody has 

 noticed that if the foliage expands in spring too soon, it 

 is very apt to get nipped ofl' by a late return of morning 

 rime. That suggests how much need the buds have 

 for a close, warm covering. Indeed, Mr. Darwin has 

 shown that leaves arc astonishingly sensiti\e even to 

 comparatively slight changes of temperature, and that 

 the so-called sleep of leaves, and many other curious 

 modes of motion in plants, are due to the neces- 

 sity for protecting the foliage from nightly chills. 

 Those delicate plants which, in the course of their spon- 

 taneous variations, happened to hit out any peculiarity 

 tending towards self-preservation in this direction, have 

 gone on and thrived ; those which failed to do so have 

 been cut off generation after generation by every colder 

 night. Now, what is thus true of the vital matter in 

 leaves generally, is especially true of the vital matter in 

 very young and undeveloped leaves. It cannot resist the 

 .slightest frost Donee natural selection has in the course 

 of long ages ensured the best possible means for keeping 

 the true inner bud warm and snug. If you pick off some 

 of these small brown scales, you will sec how closely they 

 are packed together, overlapping one another in regular 

 rows, or imbricated as the technical botanists call it That 

 is an unusually good word, imbricated, by way of scientific 

 terminology ; for it means, arranged like tiles on a roof ; 

 and in fact the scales do really lap over one another just 

 like the Italian tiles that one sees on cottages in Southern 

 ]''urope. These short, broad, brown, close-set scales are 

 tliemselves by origin abortive leaves ; or, to put it more 

 truly, they arc leaves which have given up their original func- 

 tion of digesting fresh material from the air, and have taken 

 to the new function of protecting their more active sisters 

 from the .sharp teeth of the fro.st Underneath the brown 

 out<"r pieces, however, you come at last to some tiny bright 

 green knobs ; and these shapeless little things are the living 

 parts which carry on the continuity of the bvisli from one 

 season to another. As soon as spring sets in, they will be 

 supplied with fresh living material from the reserve stores in 

 the permanent tissues of the hawthorn, and they will then 

 swell quickly within the brown covering, showing at first 

 a little pinkish tip, and finally spreading out as thin, pale 

 green leaves, full of very active chlorophyll — giving them 

 the beautiful spring hue which we all love and admire so 



