The Variation of Animals and Plants under Domestication — Volume 1

This latter plant, in its cultivated state, differs in scarcely any character from the wild English carrot, except in general luxuriance and in the size and quality of its roots; but ten varieties, differing in the colour, shape, and quality of the root, are cultivated in England and come true by seed. (9/80. Loudon's 'Encyclop. of Gardening' page 835.) Hence with the carrot, as in so many other cases, for instance with the numerous varieties and sub-varieties of the radish, that part of the plant which is valued by man, falsely appears alone to have varied. The truth is that variations in this part alone have been selected; and the seedlings inheriting a tendency to vary in the same way, analogous modifications have been again and again selected, until at last a great amount of change has been effected.

With respect to the radish, M. Carriere, by sowing the seed of the wild Raphanus raphanistrum in rich soil, and by continued selection during several generations, raised many varieties, closely like the cultivated radish (R. sativus) in their roots, as well as the wonderful Chinese variety, R. caudatus: (see 'Journal d'Agriculture pratique' tome 1 1869 page 159; also a separate essay 'Origine des Plantes Domestiques' 1869.) Raphanus raphanistrum and sativus have often been ranked as distinct species, and owing to differences in their fruit even as distinct genera; but Professor Hoffman ('Bot. Zeitung' 1872 page 482) has now shown that these differences, remarkable as they are, graduate away, the fruit of R. caudatus being intermediate. By cultivating R. raphanistrum during several generations (ibid 1873 page 9), Professor Hoffman also obtained plants bearing fruits like those of R. sativus.

PEA (Pisum sativum).

Most botanists look at the garden-pea as specifically distinct from the field-pea (P. arvense). The latter exists in a wild state in Southern Europe; but the aboriginal parent of the garden-pea has been found by one collector alone, as he states, in the Crimea. (9/81. Alph. De Candolle 'Geograph. Bot.' 960. Mr. Bentham 'Hort. Journal' volume 9 1855 page 141 believes that garden and field peas belong to the same species, and in this respect he differs from Dr. Targioni.) Andrew Knight crossed, as I am informed by the Rev. A. Fitch, the field-pea with a well-known garden variety, the Prussian pea, and the cross seems to have been perfectly fertile. Dr. Alefield has recently studied (9/82. 'Botanische Zeitung' 1860 s. 204.) the genus with care, and, after having cultivated about fifty varieties, concludes that certainly they all belong to the same species. It is an interesting fact already alluded to, that, according to O. Heer (9/83. 'Die Pflanzen der Pfahlbauten' 1866 s. 23.) the peas found in the lake-habitations of Switzerland of the Stone and Bronze ages, belong to an extinct variety, with exceedingly small seeds, allied to P. arvense or the field-pea. The varieties of the common garden-pea are numerous, and differ considerably from one another. For comparison I planted at the same time forty-one, English and French varieties. They differed greatly in height, — namely from between 6 and 12 inches to 8 feet (9/84. A variety called the Rounciva attains this height, as is stated by Mr. Gordon in 'Transact. Hort. Soc.' 2nd series volume 1 1835 page 374 from which paper I have taken some facts.), — in manner of growth, and in period of maturity. Some differ in general aspect even while only two or three inches in height. The stems of the Prussian pea are much branched. The tall kinds have larger leaves than the dwarf kinds, but not in strict proportion to their height: — HAIR'S DWARF MONMOUTH has very large leaves, and the POIS NAIN HATIF, and the moderately tall BLUE PRUSSIAN, have leaves about two-thirds of the size of the tallest kind. In the DANECROFT the leaflets are rather small and a little pointed; in the QUEEN OF DWARFS rather rounded; and in the QUEEN OF ENGLAND broad and large. In these three peas the slight differences in the shape of the leaves are accompanied by slight differences in colour, in the POIS GEANT SANS PARCHEMIN, which bears purple flowers, the leaflets in the young plant are edged with red; and in all the peas with purple flowers the stipules are marked with red.

In the different varieties, one, two, or several flowers in a small cluster, are borne on the same peduncle; and this is a difference which is considered of specific value in some of the Leguminosae. In all the varieties the flowers closely resemble each other except in colour and size. They are generally white, sometimes purple, but the colour is inconstant even in the same variety. In WARNER'S EMPEROR, which is a tall kind, the flowers are nearly double the size of the POIS NAIN HATIF; but HAIR'S DWARF MONMOUTH, which has large leaves, likewise has large flowers. The calyx in the VICTORIA MARROW is large, and in BISHOP'S LONG POD the sepals are rather narrow. In no other kind is there any difference in the flower.

The pods and seeds, which with natural species afford such constant characters, differ greatly in the cultivated varieties of the pea; and these are the valuable, and consequently the selected parts. SUGAR PEAS, or POIS SANS PARCHEMIN, are remarkable from their thin pods, which, whilst young, are cooked and eaten whole; and in this group, which, according to Mr. Gordon includes eleven sub-varieties, it is the pod which differs most; thus LEWIS'S NEGRO-PODDED PEA has a straight, broad, smooth, and dark- purple pod, with the husk not so thin as in the other kinds; the pod of another variety is extremely bowed; that of the POIS GEANT is much pointed at the extremity; and in the variety "A GRANDS COSSES" the peas are seen through the husk in so conspicuous a manner that the pod, especially when dry, can hardly at first be recognised as that of a pea.

In the ordinary varieties the pods also differ much in size; — in colour, that of WOODFORD'S GREEN MARROW being bright-green when dry, instead of pale brown, and that of the purple-podded pea being expressed by its name; — in smoothness, that of DANECROFT being remarkably glossy, whereas that of the NE PLUS ULTRA is rugged; in being either nearly cylindrical, or broad and flat; — in being pointed at the end, as in THURSTON'S RELIANCE, or much truncated, as in the AMERICAN DWARF. In the AUVERGNE PEA the whole end of the pod is bowed upwards. In the QUEEN OF THE DWARFS and in SCIMITAR PEAS the pod is almost elliptic in shape. I here give drawings of the four most distinct pods produced by the plants cultivated by me.

(FIGURE 41. PODS AND PEAS. I. Queen of Dwarfs. II. American Dwarf. III. Thurston's Reliance. IV. Pois Geant sans parchemin. a. Dan O'Rourke Pea. b. Queen of Dwarfs Pea. c. Knight's Tall White Marrow. a. Lewis's Negro Pea.)

In the pea itself we have every tint between almost pure white, brown, yellow, and intense green; in the varieties of the SUGAR PEAS we have these same tints, together with red passing through fine purple into a dark chocolate tint. These colours are either uniform or distributed in dots, striae, or moss-like marks; they depend in some cases on the colour of the cotyledons seen through the skin, and in other cases on the outer coats of the pea itself. In the different varieties, the pods contain, according to Mr. Gordon, from eleven or twelve to only four or five peas. The largest peas are nearly twice as much in diameter as the smallest; and the latter are not always borne by the most dwarfed kinds. Peas differ much in shape, being smooth and spherical, smooth and oblong, nearly oval in the QUEEN OF THE DWARFS, and nearly cubical and crumpled in many of the larger kinds.

With respect to the value of the differences between the chief varieties, it cannot be doubted that, if one of the tall SUGAR-PEAS, with purple flowers, thin-skinned pods of an extraordinary shape, including large, dark-purple peas, grew wild by the side of the lowly QUEEN OF THE DWARFS, with white flowers, greyish-green, rounded leaves, scimitar-like pods, containing oblong, smooth, pale-coloured peas, which became mature at a different season: or by the side of one of the gigantic sorts, like the CHAMPION OF ENGLAND, with leaves of great size, pointed pods, and large, green, crumpled, almost cubical peas, — all three kinds would be ranked as distinct species.

Andrew Knight (9/85. 'Phil. Tract.' 1799 page 196.) has observed that the varieties of peas keep very true, because they are not crossed by insects. As far as the fact of keeping true is concerned, I hear from Mr. Masters of Canterbury, well known as the originator of several new kinds, that certain varieties have remained constant for a considerable time, — for instance, KNIGHT'S BLUE DWARF, which came out about the year 1820. (9/86. 'Gardener's Magazine' volume 1 1826 page 153.) But the greater number of varieties have a singularly short existence: thus Loudon remarks (9/87. 'Encyclopaedia of Gardening' page 823.) that "sorts which were highly approved in 1821, are now, in 1833, nowhere to be found;" and on comparing the lists of 1833 with those of 1855, I find that nearly all the varieties have changed. Mr. Masters informs me that the nature of the soil causes some varieties to lose their character. As with other plants, certain varieties can be propagated truly, whilst others show a determined tendency to vary; thus two peas differing in shape, one round and the other wrinkled, were found by Mr. Masters within the same pod, but the plants raised from the wrinkled kind always evinced a strong tendency to produce round peas. Mr. Masters also raised from a plant of another variety four distinct sub-varieties, which bore blue and round, white and round, blue and wrinkled, and white and wrinkled peas; and although he sowed these four varieties separately during several successive years, each kind always reproduced all four kinds mixed together!

With respect to the varieties not naturally intercrossing, I have ascertained that the pea, which in this respect differs from some other Leguminosae, is perfectly fertile without the aid of insects. Yet I have seen humble-bees whilst sucking the nectar depress the keel-petals, and become so thickly dusted with pollen, that it could hardly fail to be left on the stigma of the next flower which was visited. Nevertheless, distinct varieties growing closely together rarely cross; and I have reason to believe that this is due to their stigmas being prematurely fertilised in this country by pollen from the same flower. The horticulturists who raise seed-peas are thus enabled to plant distinct varieties close together without any bad consequences; and it is certain, as I have myself found, that true seed may be saved during at least several generations under these circumstances. (9/88. See Dr. Anderson to the same effect in the 'Bath Soc. Agricultural Papers' volume 4 page 87.) Mr. Fitch raised, as he informs me, one variety for twenty years, and it always came true, though grown close to other varieties. From the analogy of kidney-beans I should have expected (9/89. I have published full details of experiments on this subject in the 'Gardener's Chronicle' 1857 October 25.) that varieties thus circumstanced would have occasionally crossed; and I shall give in the eleventh chapter two cases of this having occurred, as shown (in a manner hereafter to be explained) by the pollen of the one variety having acted directly on the seeds of the other. Whether many of the new varieties which incessantly appear are due to such occasional and accidental crosses, I do not know. Nor do I know whether the short existence of almost all the numerous varieties is the result of mere change of fashion, or of their having a weak constitution, from being the product of long-continued self- fertilisation. It may, however, be noticed that several of Andrew Knight's varieties, which have endured longer than most kinds, were raised towards the close of the last century by artificial crosses; some of them, I believe, were still vigorous in 1860; but now, in 1865, a writer, speaking (9/90. 'Gardener's Chronicle' 1865 page 387.) of Knight's four kinds of marrows, says, they have acquired a famous history, but their glory has departed.

With respect to Beans (Faba vulgaris), I will say but little. Dr. Alefield has given (9/91. 'Bonplandia' 10, 1862 s. 348.) short diagnostic characters of forty varieties. Everyone who has seen a collection must have been struck with the great difference in shape, thickness, proportional length and breadth, colour, and size which beans present. What a contrast between a Windsor and Horse-bean! As in the case of the pea, our existing varieties were preceded during the Bronze age in Switzerland (9/92. Heer 'Die Pflanzen der Pfahlbauten' 1866 s. 22.) by a peculiar and now extinct variety producing very small beans. (9/93. Mr. Bentham informs me that in Poitou and the adjoining parts of France, varieties of Phaseolus vulgaris are extremely numerous, and so different that they were described by Savi as distinct species. Mr. Bentham believes that all are descended from an unknown eastern species. Although the varieties differ so greatly in stature and in their seeds, "there is a remarkable sameness in the neglected characters of foliage and flowers, and especially in the bracteoles, an insignificant character in the eyes even of botanists.")

POTATO (Solanum tuberosum).

There is little doubt about the parentage of this plant; for the cultivated varieties differ extremely little in general appearance from the wild species, which can be recognised in its native land at the first glance. (9/94. Darwin 'Journal of Researches' 1845 page 285. Sabine in 'Transact. Hort. Soc.' volume 5 page 249.) The varieties cultivated in Britain are numerous; thus Lawson (9/95. 'Synopsis of the Vegetable Products of Scotland' quoted in Wilson's 'British Farming' page 317.) gives a description of 175 kinds. I planted eighteen kinds in adjoining rows; their stems and leaves differed but little, and in several cases there was as great a difference between the individuals of the same variety as between the different varieties. The flower varied in size, and in colour between white and purple, but in no other respect, except that in one kind the sepals were somewhat elongated. One strange variety has been described which always produces two sorts of flowers, the first double and sterile, the second single and fertile. (9/96. Sir G. Mackenzie, in 'Gardener's Chronicle' 1845 page 790.) The fruit or berries also differ, but only in a slight degree. (9/97. Putsche und Vertuch 'Versuch einer Monographie der Kartoffeln' 1819 s. 9, 15. See also Dr. Anderson 'Recreations in Agriculture' volume 4 page 325.) The varieties are liable in very different degree to the attack of the Colorado potato-beetle. (9/98. Walsh 'The American Entomologist' 1869 page 160. Also S. Tenney 'The American Naturalist' May 1871 page 171.)

The tubers, on the other hand, present a wonderful amount of diversity. This fact accords with the principle that the valuable and selected parts of all cultivated productions present the greatest amount of modification. They differ much in size and shape, being globular, oval, flattened, kidney-like, or cylindrical. One variety from Peru is described (9/99. 'Gardener's Chronicle' 1862 page 1052.) as being quite straight, and at least six inches in length, though no thicker than a man's finger. The eyes or buds differ in form, position, and colour. The manner in which the tubers are arranged on the so-called roots or rhizomes is different; thus, in the gurken-kartoffeln they form a pyramid with the apex downwards, and in another variety they bury themselves deep in the ground. The roots themselves run either near the surface or deep in the ground. The tubers also differ in smoothness and colour, being externally white, red, purple, or almost black, and internally white, yellow, or almost black. They differ in flavour and quality, being either waxy or mealy; in their period of maturity, and in their capacity for long preservation.

As with many other plants which have been long propagated by bulbs, tubers, cuttings, etc., by which means the same individual is exposed during a length of time to diversified conditions, seedling potatoes generally display innumerable slight differences. Several varieties, even when propagated by tubers, are far from constant, as will be seen in the chapter on Bud-variation. Dr. Anderson (9/100. 'Bath Society Agricult. Papers' volume 5 page 127. And 'Recreations in Agriculture' volume 5 page 86.) procured seed from an Irish purple potato, which grew far from any other kind, so that it could not at least in this generation have been crossed, yet the many seedlings varied in almost every possible respect, so that "scarcely two plants were exactly alike." Some of the plants which closely resembled each other above ground, produced extremely dissimilar tubers; and some tubers which externally could hardly be distinguished, differed widely in quality when cooked. Even in this case of extreme variability, the parent-stock had some influence on the progeny, for the greater number of the seedlings resembled in some degree the parent Irish potato. Kidney potatoes must be ranked amongst the most highly cultivated and artificial races; nevertheless their peculiarities can often be strictly propagated by seed. A great authority, Mr. Rivers (9/101. 'Gardener's Chronicle' 1863 page 643.) states that "seedlings from the ash-leaved kidney always bear a strong resemblance to their parent. Seedlings from the fluke-kidney are still more remarkable for their adherence to their parent stock, for, on closely observing a great number during two seasons, I have not been able to observe the least difference, either in earliness, productiveness, or in the size or shape of their tubers."

CHAPTER 1.X

PLANTS continued — FRUITS — ORNAMENTAL TREES — FLOWERS.

FRUITS.

GRAPES. VARY IN ODD AND TRIFLING PARTICULARS.

MULBERRY.

THE ORANGE GROUP. SINGULAR RESULTS FROM CROSSING.

PEACH AND NECTARINE. BUD-VARIATION. ANALOGOUS VARIATION. RELATION TO THE ALMOND.

APRICOT.

PLUMS. VARIATION IN THEIR STONES.

CHERRIES. SINGULAR VARIETIES OF.

APPLE.

PEAR.

STRAWBERRY. INTERBLENDING OF THE ORIGINAL FORMS.

GOOSEBERRY. STEADY INCREASE IN SIZE OF THE FRUIT. VARIETIES OF.

WALNUT. NUT.

CUCURBITACEOUS PLANTS. WONDERFUL VARIATION OF.

ORNAMENTAL TREES. THEIR VARIATION IN DEGREE AND KIND. ASH-TREE. SCOTCH-FIR. HAWTHORN.

FLOWERS. MULTIPLE ORIGIN OF MANY KINDS. VARIATION IN CONSTITUTIONAL PECULIARITIES. KIND OF VARIATION. ROSES. SEVERAL SPECIES CULTIVATED. PANSY. DAHLIA. HYACINTH. HISTORY AND VARIATION OF.

[THE VINE (Vitis vinifera) (Grapes).

The best authorities consider all our grapes as the descendants of one species which now grows wild in western Asia, which grew wild during the Bronze age in Italy (10/1. Heer 'Pflanzen der Pfahlbauten' 1866 s. 28.), and which has recently been found fossil in a tufaceous deposit in the south of France. (10/2. Alph. De Candolle 'Geograph. Bot.' page 872; Dr. A. Targioni-Tozzetti in 'Jour. Hort. Soc.' vol 9 page 133. For the fossil vine found by Dr. G. Planchon see 'Nat. Hist. Review' 1865 April page 224. See also the valuable works of M. de Saporta on the 'Tertiary Plants of France.') Some authors, however, entertain much doubt about the single parentage of our cultivated varieties, owing to the number of semi-wild forms found in Southern Europe, especially as described by Clemente (10/3. Godron 'De l'Espece' tome 2 page 100.) in a forest in Spain; but as the grape sows itself freely in Southern Europe, and as several of the chief kinds transmit their characters by seed (10/4. See an account of M. Vibert's experiments by Alex. Jordan in 'Mem. de l'Acad. de Lyon' tome 2 1852 page 108.), whilst others are extremely variable, the existence of many different escaped forms could hardly fail to occur in countries where this plant has been cultivated from the remotest antiquity. That the vine varies much when propagated by seed, we may infer from the largely increased number of varieties since the earlier historical records. New hot-house varieties are produced almost every year; for instance (10/5. 'Gardener's Chronicle' 1864 page 488.) a golden-coloured variety has been recently raised in England from a black grape without the aid of a cross. Van Mons (10/6. 'Arbres Fruitiers' 1836 tome 2 page 290.) reared a multitude of varieties from the seed of one vine, which was completely separated from all others, so that there could not, at least in this generation, have been any crossing, and the seedlings presented "les analogues de toutes les sortes," and differed in almost every possible character both in the fruits and foliage.

The cultivated varieties are extremely numerous; Count Odart says that he will not deny that there may exist throughout the world 700 or 800, perhaps even 1000 varieties, but not a third of these have any value. In the catalogue of fruit cultivated in the Horticultural Gardens of London, published in 1842, 99 varieties are enumerated. Wherever the grape is grown many varieties occur: Pallas describes 24 in the Crimea, and Burnes mentions 10 in Cabool. The classification of the varieties has much perplexed writers, and Count Odart is reduced to a geographical system; but I will not enter on this subject, nor on the many and great differences between the varieties. I will merely specify a few curious and trifling peculiarities, all taken from Odart's highly esteemed work (10/7. Odart 'Ampelographie Universelle' 1849.) for the sake of showing the diversified variability of this plant. Simon has classed grapes into two main divisions, those with downy leaves, and those with smooth leaves, but he admits that in one variety, namely the Rebazo, the leaves are either smooth, or downy; and Odart (page 70) states that some varieties have the nerves alone, and other varieties their young leaves, downy, whilst the old ones are smooth. The Pedro-Ximenes grape (Odart page 397) presents a peculiarity by which it can be at once recognised amongst a host of other varieties, namely, that when the fruit is nearly ripe the nerves of the leaves or even the whole surface becomes yellow. The Barbera d'Asti is well marked by several characters (page 426), amongst others, "by some of the leaves, and it is always the lowest on the branches, suddenly becoming of a dark red colour." Several authors in classifying grapes have founded their main divisions on the berries being either round or oblong; and Odart admits the value of this character; yet there is one variety, the Maccabeo (page 71), which often produces small round, and large oblong, berries in the same bunch. Certain grapes called Nebbiolo (page 429) present a constant character, sufficient for their recognition, namely, "the slight adherence of that part of the pulp which surrounds the seeds to the rest of the berry, when cut through transversely." A Rhenish variety is mentioned (page 228) which likes a dry soil; the fruit ripens well, but at the moment of maturity, if much rain falls, the berries are apt to rot; on the other hand, the fruit of a Swiss variety (page 243) is valued for well sustaining prolonged humidity. This latter variety sprouts late in the spring, yet matures its fruit early; other varieties (page 362) have the fault of being too much excited by the April sun, and in consequence suffer from frost. A Styrian variety (page 254) has brittle foot-stalks, so that the clusters of fruit are often blown off; this variety is said to be particularly attractive to wasps and bees. Other varieties have tough stalks, which resist the wind. Many other variable characters could be given, but the foregoing facts are sufficient to show in how many small structural and constitutional details the vine varies. During the vine disease in France certain old groups of varieties (10/8. M. Bouchardat in 'Comptes Rendus' December 1, 1851 quoted in 'Gardener's Chronicle' 1852 page 435. See also C.V. Riley on the manner in which some few of the varieties of the American Labruscan Vine escape the attacks of the Phylloxera: 'Fourth Annual Report on the Insects of Missouri' 1872 page 63 and 'Fifth Report' 1873 page 66.) have suffered far more from mildew than others. Thus "the group of Chasselas, so rich in varieties, did not afford a single fortunate exception;" certain other groups suffered much less; the true old Burgundy, for instance, was comparatively free from disease, and the Carminat likewise resisted the attack. The American vines, which belong to a distinct species, entirely escaped the disease in France; and we thus see that those European varieties which best resist the disease must have acquired in a slight degree the same constitutional peculiarities as the American species.

WHITE MULBERRY (Morus alba).

I mention this plant because it has varied in certain characters, namely, in the texture and quality of the leaves, fitting them to serve as food for the domesticated silkworm, in a manner not observed with other plants; but this has arisen simply from such variations in the mulberry having been attended to, selected, and rendered more or less constant. M. de Quatrefages (10/9. 'Etudes sur les Maladies actuelles du Ver a Soie' 1859 page 321.) briefly describes six kinds cultivated in one valley in France: of these the AMOUROUSO produces excellent leaves, but is rapidly being abandoned because it produces much fruit mingled with the leaves: the ANTOFINO yields deeply cut leaves of the finest quality, but not in great quantity: the CLARO is much sought for because the leaves can be easily collected: lastly, the ROSO bears strong hardy leaves, produced in large quantity, but with the one inconvenience, that they are best adapted for the worms after their fourth moult. MM. Jacquemet-Bonnefont, of Lyon, however, remark in their catalogue (1862) that two sub-varieties have been confounded under the name of the roso, one having leaves too thick for the caterpillars, the other being valuable because the leaves can easily be gathered from the branches without the bark being torn.

In India the mulberry has also given rise to many varieties. The Indian form is thought by many botanists to be a distinct species; but as Royle remarks (10/10. 'Productive Resources of India' page 130.), "so many varieties have been produced by cultivation that it is difficult to ascertain whether they all belong to one species;" they are, as he adds, nearly as numerous as those of the silkworm.

THE ORANGE GROUP.

We here meet with great confusion in the specific distinction and parentage of the several kinds. Gallesio (10/11. 'Traite du Citrus' 1811. 'Teoria della Riproduzione Vegetale' 1816. I quote chiefly from this second work. In 1839 Gallesio published in folio 'Gli Agrumi dei Giard. Bot. di Firenze' in which he gives a curious diagram of the supposed relationship of all the forms.), who almost devoted his life-time to the subject, considers that there are four species, namely, sweet and bitter oranges, lemons, and citrons, each of