June i i, 1896J 



NA TURE 



i.>9 



fails to see minute differences which are perceptible enough to 

 the raiser or his workmen. Nor must it he thought that these 

 variations, difficult as they are to recognise in the beginning, are 

 unimportant. On the contrary, they are interesting, physiologic- 

 ally, as the i»tunlial origin of new species, and very often they 

 are commercially valuable also. These apparently trifling 

 morphological differences are often associated with physiological 

 variations which render some varieties, say of wheat, much better 

 enabled to resist mildew and disease generally than others. 

 Some, again, prove to be better adapted for certain soils or for 

 some climates than others ; some are less liable to injury from 

 predatory birds than others, and so on. These co-relations, then, 

 are matters of the greatest importance t" the biologist intent 

 u|vin the study of progressive modification, and to the merchant 

 and the cultivator for practical reasons. 



So far we have been alluding to variations in the plant as grown 

 from seed, but similar changes are observable in the ordinary 

 buds, and gardeners are not slow to take advantage of these 

 variations. The buds taken from the base of a plant not 

 unfrecjuently differ from those which are developed higher up, 

 and these differences are perpetuated by propagation by means 

 of cuttings or grafts. An interesting illustration of the 

 variability in flower - buds is furnished by the gigantic 

 Chrysanthemums which attract so much attention in late 

 autumn. Without entering into technical details, it may be 

 briefly stated that the cultivator selects certain buds, or one 

 bud occupying a special position, and pinches off and 

 rejects most or all the others. The result is not only a flower- 

 head of large size, such as we might exjiect under the circum- 

 stances, but also, in very many cases, one which presents 

 diflferent characteristics to those which are manifested by the 

 other buds when allowed to develop themselves. "As like as 

 two |ieas in a pod " is, therefore, a motto which has not the 

 significance it had before we had observed that the peas are 

 mostly difi'erent, sometimes very much so, and the same thing 

 happens, as has been shown, in the ordinary leaf- and flower- 

 buds ; doubtless each cell has its peculiarity, which only awaits 

 a Rdntgen ray or some other means to become visible. 



Before we leave the subject of buds, some mention may be 

 made of that form of bud-variation which the gardeners speak of 

 as •' sporting." Sports are bud-variations which occur suddenly, 

 without assignable cause, and often simultaneously in different 

 regions widely separate. Thus we get jjeaches and nectarines 

 on the same bough, black and white grapes on the same shoot, 

 or even in the same bunch, finely-cut leaves on a branch that 

 normally produces broad or entire leaxes, and so on. The 

 gardener who is on the alert takes care to remove such buds, 

 and to propagate them by cuttings or grafts. If raised from 

 cuttings or layers, the duration of the sport is indefinite ; if pro- 

 pagated by grafting, their duration is naturally conditioned by 

 the life of the stock. The problems afforded by sports are of 

 great interest, and are by no means fully solved. Many of them 

 may arise from atavism, or a reversion to an ancestral condition ; 

 but of this there is no proof, neither can we appreciate the 

 reason why such reversion should take place. Some may be the 

 result of the dissociation of previously mixed characteristics. Of 

 this we frequently see unmistakable evidence. Thus hybrid 

 berberries frequently show on the same plant an un-mixing or 

 separation of the characters belonging to the two parent-forms. 



This brings us to the subject of cross-breeding as a means of 

 obtaining new or improved varieties. Cross-breeding may occur 

 in all degrees from the case where the pollen of one flower is 

 transferred, by insect or other agency, to the stigma of another 

 on the same branch, to that in which the pollen is transferred 

 to the flower on a plant of a different species. Watch a bee 

 travelling over the great disc of a sun-flo«er, and it will become 

 obvious that (always provided the stigmas be in a receptive 

 condition) cross-fertilisation of neighbouring flowers must take 

 place. 



There are endless adaptations which ensure cross-fertili-sation, 

 and on the other hand there are very numerous structural arrange- 

 ments which necessitate clo.se fertilisation, or the fertilisation of a 

 flower's ovules by pollen produced in the same blossom. In 

 view of the copious literature on this matter, it is not necessary 

 here to enter into further detail. It is enough to say that some 

 of the most .astonishing results of the gardener's art are due to 

 this practice of repeated cross-fertilisation. When the cross is 

 effected between plants of two different species the term 

 " hybridisation " is made use of, but it is obvious that there is 

 only a difference of degree between the fertilisation of difterent 



NO. 1389, VOL. 54] 



flowers on the same plant and that of flowers belonging to 

 different species, or even genera. 



The tuberous Begonias, before alluded to, are the results of 

 the successive intercrossing or hybridisation of several species, 

 and the result is the production, within little more than a 

 quarter of a century, of a race or garden-group, not to be matched 

 in nature, and so distinct as to have been thought worthy not 

 merely of specific but of generic rank. 



Many recognised genera, we might even say most, are not so 

 sharply differentiated as are these Begonias from others of 

 the same family. These extreme crosses apparently are not 

 efi'ected under natural conditions, and some botanists 

 even hesitate to admit the occurrence of hybrids in 

 nature except under very exceptional circumstances. The 

 gardeners and cultivators, however, have long considered certain 

 forms to be of hybrid origin, and one of the most interesting 

 things in this connection of late years is the positive evidence 

 which cultivators have been able to bring forward as to the 

 existence and the parentage of natural hybrids. Certain orchids, 

 now rather numerous, were, from the appearances they pre- 

 sented, assumed to be "natural hybrids" between certain 

 species. That such assumptions were correct has now been 

 proved by the production in our orchid houses of forms indis- 

 tinguishable from those met with in a wild condition, as the 

 direct consequence of the designed fertilisation of one flower by 

 the pollen of another. 



Fairchild, a nurseryman at Hoxton, and the founder of 

 the Flower-sermon, was the first on record to raise a hybrid 

 Pink. Indeed, this is the first artificial hybrid of any kind 

 on record, and it dates from 1719. From that time to 

 this gardeners have gone on selecting, cross-breeding, 

 hybridising. At one time some good folk looked askance 

 at such operations as an interference with the laws of Pro- 

 vidence. So much was this the case, that one eminent 

 firm of nurserymen in the early part of the century led their 

 customers to believe that certain heaths (Ericas), which they had 

 for sale, were imported direct from the Cape of Good Hope, 

 instead of having been raised by cross-fertilisation in their own 

 nurseries at Tooting ! 



Gardeners for the most part pursue their experiments 

 with no scientific aim. The names of Philip Miller, Thomas 

 Andrew Knight, and of Dean Herbert, amongst others, 

 suffice to show that some gardeners appreciate the deep 

 scientific value of these every-day procedures. From the 

 labours of these men and their successors it is made obvious 

 that the cultivator, by availing himself of natural tendencies and 

 natural agencies, and by his power of eliminating conflicting or 

 unpropitious elements, does actually bring about, in a relatively 

 very short period, the same results that occur under natural 

 conditions only after the lapse of a prolonged period. Do not 

 these facts show the desirability for our own biologists to study 

 carefully the results obtained by the gardener, and better still to 

 enter, as their great leader Darwin did, the field themselves as 

 experimenters. 



There can be few departments in which greater promise of 

 important results can be held out. 



JI.\.\\VELL T. Masters. 



THE ROYAL OBSERVATORY, GREENWICH. 



C\^ Saturday last, the Astronomer Royal presented his annual 

 ^^^ report to the Board of Visitors of the Royal Observatory, 

 Greenwich. Following the usual custom, a number of astro- 

 nomers and other men of science were invited to inspect the 

 buildings and instruments of the observatory. The subjoined ex- 

 tracts from the report give a general idea of progress made in 

 some departments since the middle of May last year. 



Work ivtih Equatorials. 



The new equatorial with photographic telescope of 26 inches, 

 presented by Sir Henry Thompson, is now nearly finished and 

 ready for inspection at Sir Howard Grvibb's works. Sir Henry 

 Thompson has completed his valuable gift by the addition of a 

 Cassegrain reflecting telescope of 30 inches aperture, to be 

 carried in place of the counterpoise at the other end of the de- 

 clination axis. 



The 28-inch refractor has been in constant use for micrometric 

 observations during the year, and for spectroscopic observations 

 till November last year. 



The measures of the dimensions Oi Saturn and his rings. 



