260 



KNOWLEDGE 



[November 1, 1899. 



least, secure the isolation required, and must, therefore, 

 have played an important part in bringing about these 

 extraordinary co-adaptations. It is held by some that the 

 very complete adaptations in orchids to cross-fertilization 

 could not have been possible but for the long interval that 

 elapses between the pollination of the stigma and the 

 impregnation of the ovule by the pollen-tube. Be this as 

 it may, orchids are exceedingly liable to vary, and there- 

 fore furnish abundant materials upon which natural 

 selection can work. But natural selection only comes into 

 operation with favourable variations, and, so far as orchids 

 are concerned, it is by no means certain that variations 

 which favour intercrossing are advantageous. Notwith- 

 standing the wonderful contrivances for facilitating 

 intercrossing, self-fertilization occurs extensively through- 

 out the order. Many of the most abundant orchids 

 habitually fertilize themselves. The fly orchis is even 

 more fertile with its own pollen than when crossed. The 

 structure of some orchids is such as entirely to prevent 

 spontaneous self-fertilization ; nevertheless, they are per- 

 fectly fertile with their own pollen when artificially 

 fertilized. Henslow will even have it that crossing, so far 

 from being advantageous, is a decided disadvantage to the 

 plants. On this view the first modification of flowers arose 

 from degeneration brought about by the interference of 

 insects. Only when this process had gone so far, and 

 consequent malformations had been produced which 

 rendered self-fertilization difficult or impossible, did the 

 necessity for crossing arise. Not till then could natural 

 selection begin to tell in the production of contrivances for 

 intercrossing. The orchid poUinia result, no doubt, partly 

 from the arrested development of the pollen grains and 

 their mother-cells, but it is hard to believe that such an 

 elaborate structure as the rostellura is merely due to 

 degeneration or arrested development. Even if it could be 

 shown that self-fertilization was more prevalent and 

 eliectual than it is, we should have diiSculty in accepting 

 the view that the elaborate arrangements in flowers for 

 cross-fertilization have been called into being with no 

 direct or primary reference to the interests of the flowers 

 themselves. While Henslow's explanation is just the 

 inverse of Darwin's, both are probably somewhat one- 

 sided. As the stability of the solar system depends alike 

 on the centrifugal and centripetal forces, so it may be in 

 the organic world. It is conceivable that self-fertilization 

 may be advantageous perhaps in the way of fixing or 

 transmitting acquired characters while cross-fertilization 

 may be beneficial in other directions. Nature at least does 

 not incautiously discard either alternative, but prefers to 

 retain both, fulfilling herself in many ways, 



*' Lest one good custom should corrupt the world." 



The orchids are an exceedingly numerous order, the 

 Compositse among flowering plants alone excel them in 

 respect of variety. Upwards of eight thousand species are 

 known, of which about forty are British. The bright- 

 coloured kinds are, however, only a small minority ; a vast 

 number have comparatively unattractive, valueless flowers. 

 The task of the orchid hunter is by no means easy, he may 

 travel far and incur many risks before he discovers a flower 

 sufficiently attractive to repay cultivation. A collection 

 of tropical orchids awakens in us feelings not unlike those 

 of which we are conscious in visiting a menagerie. These 

 feelings would doubtless vanish could we see the flowers 

 amid their native haunts and natural surroundings. 

 Their strange and grotesque forms appeal to our curiosity ; 

 their endless variety of colouring excites our admiration. 

 There is the azure Vanda of the Himalayas, with its great 

 profusion of blossom, a single plant according to Sir 

 Joseph Hooker sometimes bears three hundred or four 



hundred flowers in one season. Again we have the 

 Dendrobriums with their exquisite contrasts, the Oncidiums 

 with their soft delicate tints, the rich white and crimson 

 hues of the stately Cattleyas, the Lselias, the Cselogynes, 

 the Odontoglossums, and a host of others equal in splendour. 

 Yet, withal, these eccentricities of Nature, beautiful, elegant, 

 and interesting as they are, lack for us that homely grace 

 and charm which the associations of childhood have thrown 

 around the more familiar flowers of our native land. 



ON THE DUTY OF A FIELD NATURALIST. 

 ByE. A. S. E. 



WANDERINGS amongst the banks and braes, 

 and o'er the billowy ocean and mountain 

 crag have evolved some of the grandest 

 thinkers of the age — Darwin, Owen, Huxley, 

 were all field naturalists of the highest type, 

 and surely all of us are better for their writings. 



After all, field naturalist is but a trivial name given to 

 one who, if he be a naturalist at all, is at heart a natural 

 philosopher, seeking amongst the secrets of Nature the 

 evidence of truth. It is for him to "labour and to wait " ; 

 full well he feels that — 



" Art is long and time is fleeting, 



And our hearts, tlio' strong and brave, 

 Still like muffled drums are beating 

 Fuuei'al marches to the grare." 



Who has not felt a thrill of emotion on hearing that 

 harbinger of spring — the cuckoo — for the first time on an 

 April morn, a feeling of thankfulness for having lived to 

 see another year burst forth into promise, or yet when the 

 skylark, springing upwards to the very vault of heaven 

 itself, pours forth its love-inspired song in tuneful ecstasy; 

 or, again, in the solitude of the moorland hills, has not 

 been struck by the impressiveness of the scene — 



" Where the t'ox lores to kennel and buzzard to soar, 

 All boundless and free o'er the rugged Dartmoor." 



It seems incomprehensible that anyone can live in a 

 state of utter indifference to the bountiful gifts of Nature 

 met with on every hand, yet there are those who have a 

 positive dislike for things of the field, whilst as for wishing 

 to know anything about their economy, that passes their 

 wit altogether. 



I have been brought more in contact with birds than 

 any other subject of natural history, so I naturally turn 

 to them for an expression of my thoughts, and, singularly 

 enough, it is to be found in their nomenclature. Many of 

 these names were given by one of the greatest field 

 naturalists who ever lived — Linnteus, and so we often get 

 summed up in one little Latin or Greek word the chief 

 characteristic of the species, simply because of his obser- 

 vations in the field. For instance, Ccehbs, a bachelor, 

 is the specific name given to the Chafiinch because the 

 males flock together in the autumn and keep separately 

 from the females until pairing time comes again. 



The genus Phylloscopiis (from 4'i'AAov, a leaf, and (TKOiriui, 

 I look at) derives its name from the habit these little 

 warblers have of searching amongst the foliage for 

 the tiny insects they feed on. The Great Grey Shrike 

 (Lanius excuhitor) indicates the bird's habits to a nicety. 

 Lanius, a butcher, and excuhitor, a sentinel or watchman, 

 from this bird's habit of perching on the topmost twig of a 

 bush on the look-out either for prey to butcher and impale, 

 or an enemy to avoid. The genus Lagopus derives its 

 name from the fact that the legs of the grouse by their 

 complete covering (in winter) of short hair-like feathers 

 resemble those of a hare [Lnjopus, XayojiroCs, from Xay^s, 



