Chapter 46

If it had been possible to apply this principle to twisted and fasciated plants, and perhaps even to other monstrosities, I think that it will readily be granted that the chance of bringing even these races up to a percentage of 90% would have been large enough. But the large size of the cultures required for the counting of numerous groups of offspring in the adult state has deterred me from making such trials. Recently however, I have discovered a species, _Viscaria oculata_ which allows of counting twisted specimens in the pans, and I may soon be able to obtain proofs of this assertion. The validity of the hereditary percentage as a standard of selection has, within the last few years, been recognized and defended by two eminent breeders, W.A. Hays in this country and Von Lochow in Germany. Both of them have started from the experience of breeders of domestic animals. Von Lochow applied the principle to rye. He first showed how fallacious the visible characters often are. For instance the size of the kernels is often dependent on their number in the head, and if this number is [822] reduced by the injurious varietal mark of lacunae (Luckigkeit), the whole harvest will rapidly deteriorate by the selection of the largest kernels from varieties which are not quite free from this hereditary deficiency.

In order to estimate the value of his rye plants, he gathers the seed of each one separately and sows them in rows. Each row corresponds to a parent plant and receives 200 or 150 seeds, according to the available quantity. In this way from 700 to 800 parent plants are tested yearly. Each row is harvested separately. The number of plants gives the average measure of resistance to frost, this being the only important cause of loss. Then the yield in grain and straw is determined and calculated, and other qualities are taken into consideration. Finally one or more groups stand prominent above all others and are chosen for the continuation of the race. All other groups are wholly excluded from the "elite," but among them the best groups and the very best individuals from lesser groups are considered adequate for further cultivation, in order to produce the commercial product of the race.

As a matter of fact the rye of Von Lochow is now one of the best varieties, and even surpasses the celebrated variety of Schlanstedt. It was only after obtaining proof of the validity [823] of his method that Von Lochow decided to give it to the public.

W.M. Hays has made experiments with wheat at the Minnesota Agricultural Experiment Station. He chose a hundred grains as a proper number for the appreciation of each parent plant, and hence has adopted the name of "centgener power" for the hereditary percentage.

The average of the hundred offspring is the standard to judge the parent by. Experience shows at once that this average is not at all proportional to the visible qualities of the parent. Hence the conclusion that the yield of the parent plant is a very uncertain indication of its value as a parent for the succeeding generation. Only the parents with the largest power in the centgener of offspring are chosen, while all others are wholly discarded. Afterwards the seeds of the chosen groups are propagated in the field until the required quantities of seed are obtained.

This centgener power, or breeding ability, is tested and compared for the various parent plants as to yield, grade, and percentage of nitrogenous content in the grain, and as to the ability of the plant to stand erect, resist rust, and other important qualities. It is evident that by this test of a hundred specimens a far better [824] and much more reliable determination can be made than on the ground of the minutest examination of one single plant. From this point of view the method of Hays commands attention. But the chief advantage lies in the fact that it is a direct proof of that which it is desired to prove, while the visible marks give only very indirect information.

Thus the results of the men of practice are in full accordance with those of theory and scientific experiment, and there can be little doubt that they open the way for a rapid and important improvement. Once attained, progress however, will be dependent on the selection principle, and the hereditary percentage, or centgener power or breeding ability, must be determined in each generation anew. Without this the race would soon regress to its former condition.

To return to our starting point, the comparison of artificial and natural selection. Here we are at once struck by the fact that it is hardly imaginable, how nature can make use of this principle. In some measure the members of the best centgener will manifestly be at an advantage, because they contain more fit specimens than the other groups. But the struggle for existence goes on between individuals, and not between groups of brethren against groups of [825] cousins. In every group the best adapted individuals will survive, and soon the breeding differences between the parents must vanish altogether. Manifestly they can, as a rule, have no lasting result on the issue of the struggle far existence.

If now we remember that in Darwin's time this principle, breeding ability, enjoyed a far more general appreciation than at present, and that Darwin must have given it full consideration, it becomes at once clear that this old, but recently revived principle, is not adequate to support the current comparison between artificial and natural selection.

In conclusion, summing up all our arguments, we may state that there is a broad analogy between breeding selection in the widest sense of the word, including variety testing, race improvement and the trial of the breeding ability on one side, and natural selection on the other. This analogy however, points to the importance of the selection between elementary species, and the very subordinate role of intraspecific selection in nature. It strongly supports our view of the origin of species by mutation instead of continuous selection. Or, to put it in the terms chosen lately by Mr. Arthur Harris in a friendly criticism of my views: "Natural selection may explain the survival [826] of the fittest, but it cannot explain the arrival of the fittest."

A

_Abies concolor fastigiata_, 618 _Acacia_, 176, 196, 217, 458, 697 bastard, 343, 617, 618, 664, 665, 666 _Acer compestre nanum_, 612 _Achillea millefolium_, 131, 132, 441 Adaptation, 702 double, 430, 451, 452, 454, 455, 457, 458, 642 _Aegilops ovata_, 265 _speltaeformis_, 265 _Agave vivipara_, 684 _Ageratum coeruleum_, 612 _Agrostemma Coronaries bicolor_, 125 _Githago_, 282 _nicaeensis_, 162 _Agrotis_, 204 Alder, cut-leaved, 147, 596 Alfalfa, 264 Algae, 699 Allen, Grant, 237 _Alliaria_, 638 _Alnus glutinosa laciniata_, 615 Alpine plants, 437, 695, 794 _Althaea_, 490 Amaranth, 282, 452 _Amaranthus caudatus_, 282 _Amaryllis_, 272, 275, 762 brasiliensis_, 275 leopoldi_, 275 pardina_, 275 psittacina_, 275 vittata_, 275 Amen-Hotep, 697 _Ampelopsis_, 239 _Amygdalus persica laevis_, 126 _Anagallis arvensis_, 162 _Androsace_, 634 _Anemone_, 266, 331 _coronaria_, 241, 491 var. "Bride," 510 _magellanica_, 266 _sylvestris_, 266 _Anemone_, garden, 241 Annee, 760 Anomalies, taxonomic, 658, 685 _Anthemis_, 236 _nobilis_, 130 _Anthurium scherzerianum_, 639 _Antirrhinum majus_, 315 _luteum rubro-striatum_, 315 Apetalous flowers, 622 Apples, 134, 240, 328, 454, 806 elementary species, 75 method of cultivating, 76 origin of cultivated varieties, 73 use by the Romans, 74 "Wealthy," 78, 79 wild, 73, 74, 75, 76 _Aquilegia chrysantha_, 161 _Arabis ciliata glabrata_ _hirsuta glaberrima_, 126 _Aralia crassifolia_, 662 Arbres fruitiers ou Pomonomie belge, 76 _Aralia papyrifera_, 662 Arctic flora, 695 _Arnica_, 494 _montana_, 236 Aroids, 222, 631, 639 Artemisias, 131 Artificial selection, 18, 71, 77, 93, 95, 743, 744, 798, 826 first employed, 72, 92 nature of, 19 _Arum maculatum immaculatum_, 125 Ascidia, 310, 366, 367, 427, 428, 669, 670, 671, 672, 673, 674, 675 Ash, 135, 341 one-bladed, 666, 667 weeping, 196, 596 Ashe, 343 Aster, 132, 152, 242 seashore, 200, 282 _Aster Tripolium_, 132, 200, 236, 282, 410 _Astragalus alpinus_, 696 Atavism, 154, 170, 172, 175, 176, 178, 182, 185, 187, 188, 198, 220, 222, 226, 235, 344, 354, 399, 405, 411, 660, 661 bud, 183, 226 definition of, 170, 631 false, 185, 187 negative, 344 positive, 344 seed, 176 systematic, 174, 222, 630-657 Atavists, 156, 201 heredity of, 412 _Atropa Belladonna lutea_, 592 _Aubretia_, 241 _Avena fatua_, 100, 207 _Azalea_, 178, 322 _Azolla caroliniana_, 239

B

Babington, _Manual of British Botany_, 36, Bailey, 78, 306, 684 Balsams, 334 Bananas, 90, 134 Banyan, 244 Barberry, 133, 180 European, 270 purple, 596 _Barbarea vulgaris_, 427 Barley, 98, 105, 133, 203, 678, 679 "Nepaul," 203, 676, 677, 679, 681, 682 Bastard-acacia, 133, 136, 140 Bateson, 250 Bauhin, Caspar, 72, 610 Baumann, 618 Beans, 90, 152, 327, 727, 735 Bedstraw, 648 Beech, 133, 135, 242 cut-leaved, 179, 196, 616 laciniated, 196 oak-leaved, 595 purple, 196, 593, 595 Beeches, 427 fern-leaved, 147 Beets, 68, 72, 92, 93, 792, 796, 801, 815, 817, 818 Californian, 796 European, 796 forage, 71, 72, 791 salad, 71 Beet-sugar, 67, 68, 69, 70, 71, 109, 165, 717, 791, 807, 813, 814 _Begonia_, 218, 366, 509, 765 ever-flowering, 148 tuberous, 272 _clarkii_, 272 _davisii_, 272 _rosiflora_, 272 _sedeni_, 273 _semperflorens_, 133, 148, 620 _Begonia_ bulbous, 372 _veitchi_, 272 Behrens, 804 Belladonna, 145 _Bellis perennis_, 236 _perennis plena_, 195 Bentham, 237 Bentham & Hooker, _Handbook of British Flora_, 36 _Berberis_, 133, 180, 455 _ilicifolia_, 270 _vulgaris_, 270 Bertin, 596 _Berula angustifolia_, 457 Bessey, 660 _Beta maritima_, 69 _patula_, 69, 70 _vulgaris_, 69, 70 _Betula_, 132 Between-race, 358 Bewirkung, Theorie der directen (Nageli), 448 _Biastrepsis_, 402 _Bidens_, 131 _atropurpurea_, 131 _cernua_, 131, 158 _leucantha_, 131 _tripartite_, 131 Bilberries, 577 Bindweed, 41924 Binomium, of Newton, 767 Birch, 133, 243 cut-leaved, 596, 616 fastigiate, 618 fern-leaved, 179 _Bisoutella_, 282 _laevigata glabra_, 125 Bitter-sweet, 125 Blackberry, 268, 768 "Paradox," 769 Blue-bells, variation in, 54, 491, 577 Blueberries, 769 Blue-bottle, 499, 507, 509, 510 Blueflag, atavism of, 172 _Boehmeria_, 675 _bilboa_, 685 Bonnier, 439, 441, 442, 444, 451, 795 Boreau, 663 Brambles, 126, 127, 147, 239, 244, 245, 268, 740, 769, 663 _Brassica_, 244 Braun, 738 Braun and Schimper, 494 Bread-fruits, 90 Briot, 618 Britton and Brown's Flora, 162 Brooks, 711 Broom, 140 prickly, 217 Broom-rape, 220 _Broussonetia papyifera dissecta_, 616 _Brunella_, 146, 268 _vulgaris_, 577 _vulgaris alba_, 201 _Bryophyllum calycinum_, 218 Buckwheat, 452 Bud-variation, 750 Buds, adventitious, 218 Burbank, Luther, 57, 79, 116, 134, 268, 758, 768, 769, 784 Buttercup, 331, 357, 410, 725, 740 Asiatic, 241

C

Cabbages, 428, 684 atavism in, 638 origin of varieties, 621 Cactuses, 444 Cactus-dahlia, 625 _Calamintha Acinos_, 437, 452 Calamus root, 222 _Calendula officinalis_, 502 _Calliopsis tinctoria_, 195 _Calluna_, 146 _vulgaris_, 437, 577 _Caltha_, 490 _palustris_, 331 _Camelina_, 684 _Camellia_, 178, 323 _japonica_, 368 Camellias, 331 Camomile, 130, 132, 156, 366, 494, 503, 509, 512 _Campanula persicifolia_, 151, 234 _rotundifolia_, 437 Campion, 283, 302, 304 evening, 281 red, 238 _Canna_, 751, 759, 761 _indica_, 760 "Madame Crozy," 760, 761 _nepalensis_, 760 _warczewiczii_, 760 _Capsella Bursa-pastoris apetala_, 585 _heegeri_, 22, 582, 583, 684 _Carex_, 53 Carnation, 178, 241, 491 wheat-ear, 227 _Carpinus Betulus heterophylla_, 180 Carriere, 491, 596, 612, 806 Carrots, 806 Catch-fly, 419 Carboniferous period, 699 _Casuarina quadrivalvis_, 649 Cauliflowers, origin of, 621 Caumzet, 614 Causation, theory of direct, (Nageli), 448 Cedar, pyramidal, 618 Celandine, 147, 245, 280, 365 oak-leaved, 603, 610, 611 _Celosia_, 621 _Celosia cristata_, 327, 411 _Centaurea_, 242 Centgener power, 20, 822 _Centranthus macrosiphon_, 424 _Cephalotaxus_, 170, 226 _pedunculata fastigiata_, 169 Cereals, 105, 106, 107, 119, 801, 804 origin of cultivation, 104 Character-units, 632 Charlock, 424 _Cheiranthus_, 490 _Cheiri_, 370 _Cheiri gynantherus_, 371 _Chelidonium laciniatum_, 22, 609 _majus_, 147, 365, 600, 610, 611 _majus foliis quernis_, 610 Cherries, 79 Cherry, bird's, 617 Chestnuts, 427 Chromosomes, 306 _Chrysanthemum_, 178, 274 corn, 739 _Chrysanthemum carinatum_, 494 _coronarium_, 161, 202, 510 _grandiflorum_, 739 _imbricatum_, 494 _indicum_, 490 _inodorum_, 503 _inodorum plenissimum_, 336 new double, 501 _segetum_, 202, 493, 504, 729 _segetum_, var. _grandiflorum_, 43, 495, 498, 504, 504 _Chrysopogon montanus_, 450 Cieslar, 804 _Cineraria cruenta_, 514 Cinquefoil, 52 _Clarkia_, 420 _elegans_, 198 _pulchella_, 282 _pulchella carnea_, 162 _Clematis Vitalba_, 662 _Viticella nana_, 612 Clover, 80, 102, 674 crimson (Italian), 353, 358, 359, 360 five-leaved, 340, 362, 374, 431, 509, 789 four-leaved, 340, 346, 352 red, 235, 281 white, 133, 366 Clusius, 610 _Cochlearia anglica_, 52 _danica_, 52 _officinalis_, 52 Coconut, 67, 82, 83, 87, 88, 89 dispersal of, 85, 89 geographic origin of, 88,89 Coconut-palm, 84, 88 Cockerell, T.D.A., 139, 140, 591 Cocklebur, 139 Cockscomb, 165, 327, 356, 411, 621 _Cocos nucifera stupposa_, 83, 84 _cupuliformis_, 82 _rutila_, 82 _Codiaeum appendicularum_, 673 _Colchicum_, 490 _Coleus_, 132 Columbine, 725 yellow, 161 Columbus, 89, 118 Columella, 106 Composites, 130, 131, 336, 723, 778 Conifers, 168, 226, 239, 455 weeping, 617 Connation, of petals, 660, 661 "Conquests," 242 Contra-selection, 425 Cook, 84, 86, 88, 89 Corn, 81, 90, 118, 119, 135, 283, 287, 288, 775, 786, 788, 804 American, 205 Corn-cockle, 162 Corn-chrysanthemum, 739 Corn-flowers, 491, 92 Corn, "Forty-day," 118 "Harlequin," 327 sterile variety of, 622 sugar, 135, 158 "Tuscarora," 205 Corn-marigold, 493, 494 Cornel berry, yellow, 196 Cornaceae, 675 _Cornu_, 338 _Cornus Mas_, 196 Correlation, 142 _Corylus_, 133 _Avellana_, 181 _tubulosa_, 181 Cotton, 725 Cotyledon, 674 variation in, 416 _Crambe maritima_, 621 Cranesbill, 599 European, 628 meadow, 322 _Crataegus_, 196 _oxyacantha_, 132 Crowfoot, 331 corn, 283 _Crepis biennis_, 410, 411 Cress, Indian, 192 Crosses bisexual, 255, 276, 294, 298 reciprocal, 279 unisexual, 255, 261 varietal (see Hybrids) _Croton_, 673, 674 Crozy, 760, 762 Crucifers, 222, 635 _Cryptomeria_, 169, 226 _japonica_, 239 Cucumbers, 118 _Cucumis_, 52 _Cucurbita_, 52 Cultivated plants, 65, 66 elementary species of, 62 improvement of, 92 mixed nature of, 96, 118 origin of, 91 Currants, 79 Californian, 270 flowering, 166 "Gordon's," 270 Missouri, 270 white, 158 white-flowered, 167 Cuttings, 721 _Cyclamen_, 323, 355, 627, 684 Butterfly, 627 _vernum_, 619 _Cypripedium caudatum_, 487 _Cytisus adami_, 271 _candicans Attleyanus_, 367 _Laburnum_, 271 _prostratus_, 139 _prostratus ciliata_, 125 _purpureus_, 271 _spinescens_, 139

D

_Dahlia_, 131, 241, 272, 625 cactus, 625 "Jules Chretien," 628 purple-leaved, 626 "surprise," 230 tubular, 627 [sic] 274, 490, 764 first double ones, 490 green, 227, 229, 230 Daisies, 131, 132, 494 double, 195 hen-and-chicken, 514 ox-eye, 202 Shasta, 769 yellow, 202 Dandelion, 411 parthenogenesis, 61 variations in, 60 Daphne Mezereum, 146 Darwin, 1, 2, 3, 4, 5, 6, 7, 18, 76, 85, 93, 109, 110, 180, 196, 205, 206, 242, 306, 324, 338, 448, 571, 604, 612, 689, 702, 710, 715, 743, 798, 825 Darwin, George, 711 Darwinian theory, 461 basis of, 5 Date, 134 _Datura Stramonium_, 139, 142 _Stramonium inermis_, 300 _Tatula_, 139, 142, 300 Dead-nettle, 237 De Bary, 38, 47, 49 De Candolle, 76, 84, 85, 89, 228, 370, 403, 621 Alphonse, 74, 129, 226 A.P., 129 Casimir, 659, 676 De Graaff, 275 _Delphinium Ajacis_, 192 Deniau, 617 Descent, theory of, 690, 694, 702, 707, 716, 798 De Serres, Olivier, 72 _Desmodium gyrans_, 655, 656, 663, 664, 65 Dewberry, California, 269 _Dianthus barbatus_, 322, 648 twisted variety, 408 Diatoms, 699 Dictoyledons ancestors of monocotyledons, 15 _Digitalis parviflora_, 161, 640 _purpurea_, 483 pelorism of, 482 Dimorphism, 445, 447, 454, 457, 458 Dippe, 810 _Dipsacus fullonum_, 402 sylvestris_, 402, 402 Dominant character, 280 Double flowers poppies 490 production of, 489 types of, 330 Double races (see also ever-sporting varieties), 419, 427, 428 Dubois, Eugene, 712 Duchesne, 185, 188, 596 Duckweed, 222 _Draba_, 692, 693 verna, 47, 50, 51, 53, 125, 126, 518, 533, 546, 547, 561 _Dracocephalum moldavicum_, 419 Dragon-head, 419 _Drosera anglica_, 268 _filiformis_, 268 _intermedia_, 268 _obovata_, 267 _rotundifolia_, 268

E

Earth, age of, 710 Edelweiss, 438 Eichler, 660 Election, 801 Electric light, growth in, 442 Elementary species, 11, 13, 32, 67, 74, 76, 77, 78, 79, 91, 95, 116, 119, 124, 126, 128, 129, 207, 238, 252, 256, 307, 430, 435, 695, 696, 698, 702, 715, 787, 798, 800, 825 apples, 75 coconut, 82 corn, 81 cultivated plants, 62 definition of, 12, 35, 127 flax, 80 how produced, 16, 248 hybrids of, 253, 255 mutation of, 141 origin of, 459, 603 origin of, how studied, 463 selection of, 92 varieties vs., 14, 15, 141, 152, 224, 243, 247, 251, 495 Elm, 136, 219, 239, 427 _Epilobium_, 268 _hirsutum_, 683 _hirsutum cruciatum_, 588 _montanum_, 269 _tetragonum_, 269 _Equisetum Telmateja_, 642, 649 _Erica Tetralix_, 577, 661 Ericaceae, 146, 660 _Erigeron _Asteroides_, 450 _canadensis_, 132, 236, 453, 600, 695 _Erodium_, 146 _cicutarium album_, 161 _Erucastrum_, 630, 638, 639 _pollichii_, 222, 637 _Eryngium campestre_, 674 _maritimum_, 674 _Erysimum cheiranthoides_, 638 _Erythraea pulchella_, 452 _Erythrina_, 621 _Crista-galli_, 620 Eschcholtzias, 59 Esimpler, 337 _Eucalyptus citriodora_, 669 _Globulus_, 217 _Euphorbia Ipecacuanha_, 55 Evening-primrose, 62, 204, 256, 424, 686, 687, 688, 690, 691, 694, 695, 699, 702, 703, 705, 707, 708, 713, 747, 793 Evolution, 93, 685, 686, 689, 704, 707, 709, 710, 713, 718 degressive, 222, 223, 249 progression in, 630 progressive, 221, 222, 223, 248 regression in, 630 regressive, 221, 222; 223, 24 retrograde, 221, 631 Extremes, asexual multiplication of, 742, 769

F

Fabre, 265 _Fagus_, 133 _Fagus sylvatica pectinata_, 179 Fan, genealogical, 700 Fasciated stems, 409, 412 Ferns, 63 cristate, 427 plumose, 427 _Ficaria_, 53 _Ficus radicans_, 436 _religiosus_, 244 _repens_, 436 _stipulata_, 436 _ulmifolia_, 436 Figs, 436 _Filago_, 52 Fir, 134, 804 Fittest, survival of, 826 Flax, 80, 805 springing, 80 threshing, 80 white-flowered, 158, 160 Fleabane, Canada, 132, 236 Flowers, gamopetalous, 660 Fluctuability embryonic, see Fluctuation, individual Fluctuation, 708, 715, 716, 718, 719, 724, 737, 741 curves of, 729, 794 defined, 191 individual, 718, 723, 732, 741, 745, 749, 788 mutation vs. 7, 16, 719 partial, 718, 723, 732, 741, 745, 748, 749, 771 inadequate for evolution, in elementary species, 19 nature of, 18 specific and varietal characters vs. 17 Forget-me-not, 368 Fothergill, John, 521 Foxglove, 163 peloric, 164, 356, 367 yellow, 161, 640 _Fraxinus excelsior monophylla_, 667 _exheterophylla_, 667 _simplici folio_, 667 French flora (Grenier and Godron), 433 Fries on _Hieracium_, 60 Frostweed, 440 species of, 52 _Fuchsia_, 272, 355 Fuchsias, 491

G

Gaertner, 279 _Galeopsis Ladanum canescens_, 139 _Galium_, 648 _Aparine_, 409, 648 _elatum_, 52 _erectum_, 52 _Mollugo_, 62 _verum_, 648 Gallesio, 138 Galton, 736, 776 Gamopetaly, 662 Garden-pansy, origin of, 38 Garlic, 638 Gauchery, 452 Geikie, 711 Genera artificial character of, 36 polymorphous, 692 _Gentiana punctata concolor_, 125 Gentians, 577 Georgics (Vergil), 106 _Geranium pratense_, 323, 628 _album_, 628 _pyreniacum_, 599 German flora (Koth), 432 Geum, 282 Gherkins, 118 Gideon, Peter M., 78 Glacial period, 696 _Gladiolus_, 241, 272, 274, 368, 765 _cardinalis_, 275 _gandavensis_, 275 _psittacinus_, 275 _purpureo-auratus_, 275 _Glaucium_, 241 _Gleditschia sinensis_, 614 _triacanthos pendula_, 617 _Gloxinia_, 282, 485 erect, 626 _Gloxinia erecta_, 485 peloric variety, 485 _Gnaphalium Leontopodium_, 438 _Godetia amoena_, 161 Godetias, 59, 232 Godron, 265, 432 Goeppert, 370 Gooseberry, 79, 140, 626 red, 133, 165, 241 Grapes, 90, 158, 328 Grape-hyacinth, _plumosa_, 134 Grasses, 102, 631, 681 Grenier, 433 Groundsel, 132 Growth, nutrition and, 714, 720, 722 Guelder-rose, 134, 239 Gum-tree, Australian, 217 _Gypsophila paniculata_ twisted variety, 409

H