With Reseda odorata I have found certain individuals quite sterile with their own pollen, and so it is with the indigenous Reseda lutea. The self-sterile plants of both species were perfectly fertile when crossed with pollen from any other individual of the same species. These observations will hereafter be published in another work, in which I shall also show that seeds sent to me by Fritz Müller produced by plants of Eschscholtzia californica which were quite self-sterile in Brazil, yielded in this country plants which were only slightly self-sterile.
It appears[75] that certain flowers on certain plants of Lilium candidum can be fertilised more freely by pollen from a distinct individual than by their own. So, again, with the varieties of the potato. Tinzmann,[76] who made many trials with this plant, says that pollen from another variety sometimes “exerts a powerful influence, and I have found sorts of potatoes which would not bear seed from impregnation with the pollen of their own flowers would bear it when impregnated with other pollen.” It does not, however, appear to have been proved that the pollen which failed to act on the flower’s own stigma was in itself good.
In the genus Passiflora it has long been known that several species do not produce fruit, unless fertilised by pollen taken from distinct species: thus, Mr. Mowbray[77] found that he could not get fruit from P. alata and racemosa except by reciprocally fertilising them with each other’s pollen; and similar facts have been observed in Germany and France.[78] I have received two accounts of P. quadrangularis never producing fruit from its own pollen, but doing so freely when fertilised in one case with the pollen of P. cœrulea, and in another case with that of P. edulis. But in three other cases this species fruited freely when fertilised with its own pollen; and the writer in one case attributed the favourable result to the temperature of the house having been raised from 5° to 10° Fahr. above the former temperature, after the flowers were fertilised.[79] With respect to P. laurifolia, a cultivator of much experience has recently remarked[80] that the flowers “must be fertilised with the pollen of P. cœrulea, or of some other common kind, as their own pollen will not fertilise them.” But the fullest details on this subject have been given by Messrs. Scott and Robertson Munro:[81] plants of Passiflora racemosa, cœrulea, and alata flowered profusely during many years in the Botanic Gardens of Edinburgh, and, though repeatedly fertilised with their own pollen, never produced any seed; yet this occurred at once with all three species when they were crossed together in various ways. In the case of P. cœrulea three plants, two of which grew in the Botanic Gardens, were all rendered fertile, merely by impregnating each with pollen of one of the others. The same result was attained in the same manner with P. alata, but with only one plant out of three. As so many self-sterile species of Passiflora have been mentioned, it should be stated that the flowers of the annual P. gracilis are nearly as fertile with their own pollen as with that from a distinct plant; thus sixteen flowers spontaneously self-fertilised produced fruit, each containing on an average 21·3 seed, whilst fruit from fourteen crossed flowers contained 24·1 seed.
Returning to P. alata, I have received (1866) some interesting details from Mr. Robertson Munro. Three plants, including one in England, have already been mentioned which were inveterately self-sterile, and Mr. Munro informs me of several others which, after repeated trials during many years, have been found in the same predicament. At some other places, however, this species fruits readily when fertilised with its own pollen. At Taymouth Castle there is a plant which was formerly grafted by Mr. Donaldson on a distinct species, name unknown, and ever since the operation it has produced fruit in abundance by its own pollen; so that this small and unnatural change in the state of this plant has restored its self-fertility! Some of the seedlings from the Taymouth Castle plant were found to be not only sterile with their own pollen, but with each other’s pollen, and with the pollen of distinct species. Pollen from the Taymouth plant failed to fertilise certain plants of the same species, but was successful on one plant in the Edinburgh Botanic Gardens. Seedlings were raised from this latter union, and some of their flowers were fertilised by Mr. Munro with their own pollen; but they were found to be as self-impotent as the mother-plant had always proved, except when fertilised by the grafted Taymouth plant, and except, as we shall see, when fertilised by her own seedlings. For Mr. Munro fertilised eighteen flowers on the self-impotent mother-plant with pollen from these her own self-impotent seedlings, and obtained, remarkable as the fact is, eighteen fine capsules full of excellent seed! I have met with no case in regard to plants which shows so well as this of P. alata, on what small and mysterious causes complete fertility or complete sterility depends.
The facts hitherto given relate to the much-lessened or completely destroyed fertility of pure species when impregnated with their own pollen, in comparison with their fertility when impregnated by distinct individuals or distinct species; but closely analogous facts have been observed with hybrids.
Herbert states[82] that having in flower at the same time nine hybrid Hippeastrums, of complicated origin, descended from several species, he found that “almost every flower touched with pollen from another cross produced seed abundantly, and those which were touched with their own pollen either failed entirely, or formed slowly a pod of inferior size, with fewer seeds.” In the ‘Horticultural Journal’ he adds that “the admission of the pollen of another cross-bred Hippeastrum (however complicated the cross) to any one flower of the number, is almost sure to check the fructification of the others.” In a letter written to me in 1839, Dr. Herbert says that he had already tried these experiments during five consecutive years, and he subsequently repeated them, with the same invariable result. He was thus led to make an analogous trial on a pure species, namely, on the Hippeastrum aulicum, which he had lately imported from Brazil: this bulb produced four flowers, three of which were fertilised by their own pollen, and the fourth by the pollen of a triple cross between H. bulbulosum, reginæ, and vittatum; the result was, that “the ovaries of the three first flowers soon ceased to grow, and after a few days perished entirely: whereas the pod impregnated by the hybrid made vigorous and rapid progress to maturity, and bore good seed, which vegetated freely.” This is, indeed, as Herbert remarks, “a strange truth,” but not so strange as it then appeared.
As a confirmation of these statements, I may add that Mr. M. Mayes[83] after much experience in crossing the species of Amaryllis (Hippeastrum), says, “neither the species nor the hybrids will, we are well aware, produce seed so abundantly from their own pollen as from that of others.” So, again, Mr. Bidwell, in New South Wales[84] asserts that Amaryllis belladonna bears many more seeds when fertilised by the pollen of Brunswigia (Amaryllis of some authors) josephinæ or of B. multiflora, than when fertilised by its own pollen. Mr. Beaton dusted four flowers of a Cyrtanthus with their own pollen, and four with the pollen of Vallota (Amaryllis) purpurea; on the seventh day “those which received their own pollen slackened their growth, and ultimately perished; those which were crossed with the Vallota held on.”[85] These latter cases, however, relate to uncrossed species, like those before given with respect to Passiflora, Orchids, etc., and are here referred to only because the plants belong to the same group of Amaryllidaceæ.
In the experiments on the hybrid Hippeastrums, if Herbert had found that the pollen of two or three kinds alone had been more efficient on certain kinds than their own pollen, it might have been argued that these, from their mixed parentage, had a closer mutual affinity than the others; but this explanation is inadmissible, for the trials were made reciprocally backwards and forwards on nine different hybrids; and a cross, whichever way taken, always proved highly beneficial. I can add a striking and analogous case from experiments made by the Rev. A. Rawson, of Bromley Common, with some complex hybrids of Gladiolus. This skilful horticulturist possessed a number of French varieties, differing from each other only in the colour and size of the flowers, all descended from Gandavensis, a well-known old hybrid, said to be descended from G. natalensis by the pollen of G. oppositiflorus.[86] Mr. Rawson, after repeated trials, found that none of the varieties would set seed with their own pollen, although taken from distinct plants of the same variety (which had, of course, been propagated by bulbs), but that they all seeded freely with pollen from any other variety. To give two examples: Ophir did not produce a capsule with its own pollen, but when fertilised with that of Janire, Brenchleyensis, Vulcain and Linné, it produced ten fine capsules; but the pollen of Ophir was good, for when Linné was fertilised by it seven capsules were produced. This latter variety, on the other hand, was utterly barren with its own pollen, which we have seen was perfectly efficient on Ophir. Altogether, Mr. Rawson, in the year 1861 fertilised twenty-six flowers borne by four varieties with pollen taken from other varieties, and every single flower produced a fine seed-capsule; whereas fifty-two flowers on the same plants, fertilised at the same time with their own pollen, did not yield a single seed-capsule. Mr. Rawson fertilised, in some cases, the alternate flowers, and in other cases all those down one side of the spike, with pollen of other varieties, and the remaining flowers with their own pollen. I saw these plants when the capsules were nearly mature, and their curious arrangement at once brought full conviction to the mind that an immense advantage had been derived from crossing these hybrids.
Lastly, I have heard from Dr. E. Bornet, of Antibes, who has made numerous experiments in crossing the species of Cistus, but has not yet published the results, that, when any of these hybrids are fertile, they may be said to be, in regard to function, dioecious; “for the flowers are always sterile when the pistil is fertilised by pollen taken from the same flower or from flowers on the same plant. But they are often fertile if pollen be employed from a distinct individual of the same hybrid nature, or from a hybrid made by a reciprocal cross.”
Conclusion.—That plants should be self-sterile, although both sexual elements are in a fit state for reproduction, appears at first sight opposed to all analogy. With respect to the species, all the individuals of which are in this state, although living under their natural conditions, we may conclude that their self-sterility has been acquired for the sake of effectually preventing self-fertilisation. The case is closely analogous with that of dimorphic and trimorphic or heterostyled plants, which can be fully fertilised only by plants belonging to a different form, and not, as in the foregoing cases, indifferently by any other individual of the species. Some of these hetero-styled plants are completely sterile with pollen taken from the same plant or from the same form. With respect to species living under their natural conditions, of which only certain individuals are self-sterile (as with Reseda lutea), it is probable that these have been rendered self-sterile to ensure occasional cross-fertilisation, whilst other individuals have remained self-fertile to ensure the propagation of the species. The case seems to be parallel with that of plants which produce, as Hermann Müller has discovered, two forms—one bearing more conspicuous flowers with their structure adapted for cross-fertilisation by insects, and the other form with less conspicuous flowers adapted for self-fertilisation. The self-sterility, however, of some of the foregoing plants is incidental on the conditions to which they have been subjected, as with the Eschscholtzia, the Verbascum phœniceum (the sterility of which varied according to the season), and with the Passiflora alata, which recovered its self-fertility when grafted on a different stock.
It is interesting to observe in the above several cases the graduated series from plants which, when fertilised by their own pollen, yield the full number of seeds, but with the seedlings a little dwarfed in stature—to plants which when self-fertilised yield few seeds—to those which yield none, but have their ovaria somewhat developed—and, lastly, to those in which the plant’s own pollen and stigma mutually act on one another like poison. It is also interesting to observe on how slight a difference in the nature of the pollen or of the ovules complete self-sterility or complete self-fertility must depend in some of the above cases. Every individual of the self-sterile species appears to be capable of producing the full complement of seed when fertilised by the pollen of any other individual (though judging from the facts given with respect to Abutilon the nearest kin must be excepted); but not one individual can be fertilised by its own pollen. As every organism differs in some slight degree from every other individual of the same species, so no doubt it is with their pollen and ovules; and in the above cases we must believe that complete self-sterility and complete self-fertility depend on such slight differences in the ovules and pollen, and not their having been differentiated in some special manner in relation to one another; for it is impossible that the sexual elements of many thousand individuals should have been specialised in relation to every other individual. In some, however, of the above cases, as with certain Passifloras, an amount of differentiation between the pollen and ovules sufficient for fertilisation is gained only by employing pollen from a distinct species; but this is probably the result of such plants having been rendered somewhat sterile from the unnatural conditions to which they have been exposed.
Exotic animals confined in menageries are sometimes in nearly the same state as the above-described self-impotent plants; for, as we shall see in the following chapter, certain monkeys, the larger carnivora, several finches, geese, and pheasants, cross together, quite as freely as, or even more freely than the individuals of the same species breed together. Cases will, also, be given of sexual incompatibility between certain, male and female domesticated animals, which, nevertheless, are fertile when matched with any other individual of the same kind.
In the early part of this chapter it was shown that the crossing of individuals belonging to distinct families of the same race, or to different races or species, gives increased size and constitutional vigour to the offspring, and, except in the case of crossed species, increased fertility. The evidence rests on the universal testimony of breeders (for it should be observed that I am not here speaking of the evil results of close interbreeding), and is practically exemplified in the higher value of cross-bred animals for immediate consumption. The good results of crossing have also been demonstrated with some animals and with numerous plants, by actual weight and measurement. Although animals of pure blood will obviously be deteriorated by crossing, as far as their characteristic qualities are concerned, there seems to be no exception to the rule that advantages of the kind just mentioned are thus gained, even when there has not been any previous close interbreeding; and the rule applies to such animals as cattle and sheep, which can long resist breeding in-and-in between the nearest blood-relations.
In the case of crossed species, although size, vigour, precocity, and hardiness are, with rare exceptions, gained, fertility, in a greater or less degree, is lost; but the gain in the above respects can hardly be attributed to the principle of compensation; for there is no close parallelism between the increased size and vigour of hybrid offspring and their sterility. Moreover, it has been clearly proved that mongrels which are perfectly fertile gain these same advantages as well as sterile hybrids.
With the higher animals no special adaptations for ensuring occasional crosses between distinct families seem to exist. The eagerness of the males, leading to severe competition between them, is sufficient; for even with gregarious animals, the old and dominant males will be dispossessed after a time and it would be a mere chance if a closely related member of the same family were to be the victorious successor. The structure of many of the lower animals, when they are hermaphrodites, is such as to prevent the ovules being fertilised by the male element of the same individual; so that the concourse of two individuals is necessary. In other cases the access of the male element of a distinct individual is at least possible. With plants, which are affixed to the ground and cannot wander from place to place like animals, the numerous adaptations for cross-fertilisation are wonderfully perfect, as has been admitted by every one who has studied the subject.
The evil consequences of long-continued close interbreeding are not so easily recognised as the good effects from crossing, for the deterioration is gradual. Nevertheless, it is the general opinion of those who have had most experience, especially with animals which propagate quickly, that evil does inevitably follow sooner or later, but at different rates with different animals. No doubt a false belief may, like a superstition, prevail widely; yet it is difficult to suppose that so many acute observers have all been deceived at the expense of much cost and trouble. A male animal may sometimes be paired with his daughter, granddaughter, and so on, even for seven generations, without any manifest bad result: but the experiment has never been tried of matching brothers and sisters, which is considered the closest form of interbreeding, for an equal number of generations. There is good reason to believe that by keeping the members of the same family in distinct bodies, especially if exposed to somewhat different conditions of life, and by occasionally crossing these families, the evil results of interbreeding may be much diminished or quite eliminated. These results are loss of constitutional vigour, size, and fertility; but there is no necessary deterioration in the general form of the body, or in other good qualities. We have seen that with pigs first-rate animals have been produced after long-continued close interbreeding, though they had become extremely infertile when paired with their near relations. The loss of fertility, when it occurs, seems never to be absolute, but only relative to animals of the same blood; so that this sterility is to a certain extent analogous with that of self-impotent plants which cannot be fertilised by their own pollen, but are perfectly fertile with pollen of any other individual of the same species. The fact of infertility of this peculiar nature being one of the results of long-continued interbreeding, shows that interbreeding does not act merely by combining and augmenting various morbid tendencies common to both parents; for animals with such tendencies, if not at the time actually ill, can generally propagate their kind. Although offspring descended from the nearest blood-relations are not necessarily deteriorated in structure, yet some authors believe that they are eminently liable to malformations; and this is not improbable, as everything which lessens the vital powers acts in this manner. Instances of this kind have been recorded in the case of pigs, bloodhounds, and some other animals.
Finally, when we consider the various facts now given which plainly show that good follows from crossing, and less plainly that evil follows from close interbreeding, and when we bear in mind that with very many organisms elaborate provisions have been made for the occasional union of distinct individuals, the existence of a great law of nature is almost proved; namely, that the crossing of animals and plants which are not closely related to each other is highly beneficial or even necessary, and that interbreeding prolonged during many generations is injurious.
REFERENCES
[1] ‘The Art of Improving the Breed, etc.,’ 1809, p. 16.
[2] ‘The History of the Rise and Progress of the Killerby, etc. Herds,’ p. 41.
[3] For Andrew Knight, see A. Walker, on ‘Intermarriage,’ 1838, p. 227. Sir J. Sebright’s Treatise has just been quoted.
[4] ‘Cattle,’ p. 199.
[5] I give this on the authority of Nathusius, ‘Ueber Shorthorn Rindvieh,’ 1857, s. 71, (see also ‘Gardener’s Chronicle,’ 1860, p. 270). But Mr. J. Storer, a large breeder of cattle, informs me that the parentage of Clarissa is not well authenticated. In the first vol. of the ‘Herd Book,’ she was entered as having six descents from Favourite, “which was a palpable mistake,” and in all subsequent editions she was spoken of as having only four descents. Mr. Storer doubts even about the four, as no names of the dams are given. Moreover, Clarissa bore “only two bulls and one heifer, and in the next generation her progeny became extinct.” Analogous cases of close interbreeding are given in a pamphlet published by Mr. C. Macknight and Dr. H. Madden, ‘On the True Principles of Breeding;’ Melbourne, Australia, 1865.
[6] Mr. Willoughby Wood, in ‘Gardener’s Chronicle,’ 1855, p. 411; and 1860, p. 270. See the very clear tables and pedigrees given in Nathusius’ ‘Rindvieh,’ s. 72-77.
[7] Mr. Wright, ‘Journal of Royal Agricult. Soc.,’ vol. vii., 1846, p. 204. Mr. J. Downing (a successful breeder of Shorthorns in Ireland) informs me that the raisers of the great families of Shorthorns carefully conceal their sterility and want of constitution. He adds that Mr. Bates, after he had bred his herd in-and-in for some years, “lost in one season twenty-eight calves solely from want of constitution.”
[8] Youatt on Cattle, p. 202.
[9] ‘Report British Assoc., Zoolog. Sect.,’ 1838.
[10] Azara, ‘Quadrupèdes du Paraguay,’ tom. ii. pp. 354, 368.
[11] For the case of the Messrs. Brown, see ‘Gardener’s Chronicle,’ 1855, p. 26. For the Foscote flock, ‘Gardener’s Chronicle,’ 1860, p. 416. For the Naz flock, ‘Bull. de la Soc. d’Acclimat.,’ 1860, p. 477.
[12] Nathusius, ‘Rindvieh,’ s. 65; Youatt on Sheep, p. 495.
[13] ‘Gardener’s Chronicle,’ 1861, p. 631.
[14] ‘Journal R. Agricult. Soc.,’ vol. xiv., 1853, p. 212.
[15] Lord Somerville, ‘Facts on Sheep and Husbandry,’ p. 6. Mr. Spooner in ‘Journal of Royal Agricult. Soc. of England,’ vol. xx. part ii. See also an excellent paper on the same subject in ‘Gardener’s Chronicle,’ 1860, p. 321, by Mr. Charles Howard.
[16] ‘Some Account of English Deer Parks,’ by Evelyn P. Shirley, 1867.
[17] Stonehenge, ‘The Dog,’ 1867, pp. 175-178.
[18] ‘The Art of Improving the Breed,’ etc., p. 13. With respect to Scotch deerhounds, see Scrope’s ‘Art of Deer Stalking,’ pp. 350-353.
[19] ‘Cottage Gardener,’ 1861, p. 327.
[20] Mr. Huth gives (‘The Marriage of Near Kin,’ 1875, p. 302) from the ‘Bulletin de l’Acad. R. de Méd. de Belgique’ (vol. ix., 1866, pp. 287, 305), several statements made by a M. Legrain with respect to crossing brother and sister rabbits for five or six successive generations with no consequent evil results. I was so much surprised at this account, and at M. Legrain’s invariable success in his experiments, that I wrote to a distinguished naturalist in Belgium to inquire whether M. Legrain was a trustworthy observer. In answer, I have heard that, as doubts were expressed about the authenticity of these experiments, a commission of inquiry was appointed, and that at a succeeding meeting of the Society (‘Bull. de l’Acad. R. de Méd. de Belgique,’ 1867, 3rd series, Tome 1, No. 1 to 5), Dr. Crocq reported “qu’il était matériellement impossible que M. Legrain ait fait les expériences qu’il annonce.” To this public accusation no satisfactory answer was made.
[21] Sidney’s edit. of ‘Youatt on the Pig,’ 1860, p. 30; p. 33 quotation from Mr. Druce; p. 29 on Lord Western’s case.
[22] ‘Journal of Royal Agricult. Soc. of England,’ 1846, vol. vii. p. 205.
[23] ‘Ueber Rindvieh,’ etc., s. 78. Col. Le Couteur, who has done so much for the agriculture of Jersey, writes to me that from possessing a fine breed of pigs he bred them very closely, twice pairing brothers and sisters, but nearly all the young had fits and died suddenly.
[24] Sidney on the Pig, p. 36. See also note p. 34. Also Richardson on the Pig, 1847, p. 26.
[25] Dr. Dally has published an excellent article (translated in the ‘Anthropolog. Review,’ May, 1864, p. 65), criticising all writers who have maintained that evil follows from consanguineous marriages. No doubt on this side of the question many advocates have injured their cause by inaccuracies: thus it has been stated (Devay, ‘Du Danger des Mariages,’ etc., 1862, p. 141) that the marriages of cousins have been prohibited by the legislature of Ohio; but I have been assured, in answer to inquiries made in the United States, that this statement is a mere fable.
[26] See his interesting work on the ‘Early History of Man,’ 1865, chap. x.
[27] ‘The Marriage of Near Kin,’ 1875. The evidence given by Mr. Huth would, I think, have been even more valuable than it is on this and some other points, if he had referred solely to the works of men who had long resided in each country referred to, and who showed that they possessed judgment and caution. See also Mr. W. Adam, ‘On Consanguinity in Marriage’ in the ‘Fortnightly Review,’ 1865, p. 710. Also Hofacker, ‘Ueber die Eigenschaften,’ etc., 1828.
[28] Sir G. Grey’s ‘Journal of Expeditions into Australia,’ vol. ii. p. 243; and Dobrizhoffer, ‘On the Abipones of South America.’
[29] ‘Descent of Man,’ 2nd. edit. p. 524.
[30] ‘Journal of Statistical Soc.’ June, 1875, p. 153; and ‘Fortnightly Review,’ June, 1875.
[31] ‘The Art of Improving the Breed,’ p. 13.
[32] ‘The Poultry Book,’ by W. B. Tegetmeier, 1866, p. 245.
[33] ‘Journal Royal Agricult. Soc.,’ 1846, vol. vii. p. 205; see also Ferguson on the Fowl, pp. 83, 317; see also ‘The Poultry Book,’ by Tegetmeier, 1866, p. 135, with respect to the extent to which cock-fighters found that they could venture to breed in-and-in, viz., occasionally a hen with her own son; “but they were cautious not to repeat the in-and-in breeding.”
[34] ‘The Poultry Book,’ by W. B. Tegetmeier, 1866, p. 79.
[35] ‘The Poultry Chronicle,’ 1854, vol. i. p. 43.
[36] ‘The Poultry Book,’ by W. B. Tegetmeier, 1866, p. 79.
[37] ‘The Poultry Chronicle,’ vol. i. p. 89.
[38] ‘The Poultry Book,’ 1866, p. 210.
[39] Ibid. 1866, p. 167; and ‘Poultry Chronicle,’ vol. iii., 1855, p. 15.
[40] ‘A Treatise on Fancy Pigeons,’ by J. M. Eaton, p. 56.
[41] ‘The Pigeon Book,’ p. 46.
[42] ‘Das Ganze der Taubenzucht,’ 1837, s. 18.
[43] ‘Les Pigeons,’ 1824, p. 35.
[44] ‘Proc. Entomolog. Soc.,’ Aug. 6th, 1860, p. 126.
[45] ‘Journal of Horticulture,’ 1861, pp. 39, 77, 158; and 1864, p. 206.
[46] ‘Beiträge zur Kenntniss der Befruchtung,’ 1844, s. 366.
[47] ‘Amaryllidaceæ,’ p. 371.
[48] ‘De la Fécondation,’ 2nd edit., 1862, p. 79.
[49] ‘Mémoire sur les Cucurbitacées,’ pp. 36, 28, 30.
[50] Loudon’s ‘Gard. Mag.,’ vol. viii., 1832, p. 52.
[51] ‘Transact. Hort. Soc.,’ vol. i. p. 25.
[52] ‘Annal. des Sc. Nat.,’ 3rd series, Bot., tom. vi. p. 189.
[53] ‘Philosophical Transactions,’ 1799, p. 200.
[54] ‘Ueber die Bastarderzeugung,’ 1828, s. 32, 33. For Mr. Chaundy’s case, see Loudon’s ‘Gard. Mag.’ vol. vii. 1831, p. 696.
[55] ‘Gardener’s Chron.,’ 1846, p. 601.
[56] ‘Philosoph. Transact.,’ 1799, p. 201.
[57] Quoted in ‘Bull. Bot. Soc. France,’ vol. ii., 1855, p. 327.
[58] Gärtner, ‘Bastarderzeugung,’ s. 259, 518, 526 et seq.
[59] ‘Fortsetzung,’ 1763, s. 29; ‘Dritte Fortsetzung,’ s. 44, 96; ‘Act. Acad. St. Petersburg,’ 1782, part ii., p. 251; ‘Nova Acta,’ 1793, pp. 391, 394; ‘Nova Acta,’ 1795, pp. 316, 323.
[60] ‘Die Bastardbefruchtung,’ etc., 1865, s. 31, 41, 42.
[61] Max Wichura fully accepts this view (‘Bastardbefruchtung,’ s. 43), as does the Rev. M. J. Berkeley, in ‘Journal of Hort. Soc.,’ Jan. 1866, p. 70.
[62] ‘Bastarderzeugung,’ s. 394, 526, 528.
[63] Kölreuter, ‘Nova Acta,’ 1795, p. 316.
[64] Gärtner, ‘Bastarderzeugung,’ s. 430.
[65] Quoted by Dr. Murie, in ‘Proc. Zoolog. Soc.,’ 1870, p. 40.
[66] ‘Botanische Zeitung,’ Jan. 1864, s. 3.
[67] ‘Monatsbericht Akad. Wissen.’ Berlin, 1866, s. 372.
[68] International Hort. Congress, London, 1866.
[69] ‘Proc. Bot. Soc. of Edinburgh,’ May, 1863: these observations are given in abstract, and others are added, in the ‘Journal of Proc. of Linn. Soc.,’ vol. viii. Bot., 1864, p. 162.
[70] Prof. Lecoq, ‘De la Fécondation,’ 2nd edit., 1862, p. 76.
[71] ‘Jenaische Zeitschrift fur Naturwiss.’ B. vii. p. 22, 1872, and p. 441, 1873. A large part of this paper has been translated in the ‘American Naturalist,’ 1874, p. 223.
[72] ‘Bastarderzeugung,’ s. 64, 357.
[73] Ibid., s. 357.
[74] ‘Zweite Fortsetzung,’ s. 10; ‘Dritte Forts.,’ s. 40. Mr. Scott likewise fertilised fifty-four flowers of Verbascum phœniceum, including two varieties, with their own pollen, and not a single capsule was produced. Many of the pollen-grains emitted their tubes, but only a few of them penetrated the stigmas; some slight effect however was produced, as many of the ovaries became somewhat developed: ‘Journal Asiatic Soc. Bengal,’ 1867, p. 150.
[75] Duvernoy, quoted by Gärtner, ‘Bastarderzeugung,’ s. 334.
[76] ‘Gardener’s Chronicle,’ 1846, p. 183.
[77] ‘Transact. Hort. Soc.,’ vol. vii., 1830, p. 95.
[78] Prof. Lecoq ‘De la Fécondation,’ 1845, p. 70; Gärtner, ‘Bastarderzeugung,’ s. 64.
[79] ‘Gardener’s Chronicle,’ 1868, p. 1341.
[80] ‘Gardener’s Chronicle,’ 1866, p. 1068.
[81] ‘Journal of Proc. of Linn. Soc.,’ vol. viii., 1864, p. 1168. Mr. Robertson Munro, in ‘Trans. Bot. Soc.’ of Edinburgh, vol. ix. p. 399.
[82] ‘Amaryllidaceæ,’ 1837, p. 371; ‘Journal of Hort. Soc.,’ vol. ii., 1847, p. 19.
[83] Loudon’s ‘Gardener’s Magazine,’ vol. xi., 1835, p. 260.
[84] ‘Gardener’s Chronicle,’ 1850, p. 470.
[85] ‘Journal Hort. Soc.,’ vol. v. p. 135. The seedlings thus raised were given to the Hort. Soc.; but I find, on inquiry, that they unfortunately died the following winter.
[86] Mr. D. Beaton, in ‘Journal of Hort.,’ 1861, p. 453. Lecoq however (‘De la Fécond.,’ 1862, p. 369), states that this hybrid is descended from G. psittacinus and cardinalis; but this is opposed to Herbert’s experience, who found that the former species could not be crossed.