Chapter 1: IX (2)

Although we see such great differences in the shape, size, colour, arrangement, and manner of growth of the leaves and stem, and of the flower-stems in the broccoli and cauliflower, it is remarkable that the flowers themselves, the seed-pods and seeds, present extremely slight differences or none at all. (9/66. Godron 'De l'Espece' tome 2 page 52; Metzger 'Syst. Beschreibung der Kult. Kohlarten' 1833 s. 6.) I compared the flowers of all the principal kinds; those of the Couve Tronchuda are white and rather smaller than in common cabbages; those of the Portsmouth broccoli have narrower sepals, and smaller, less elongated petals; and in no other cabbage could any difference be detected. With respect to the seed-pods, in the purple Kohlrabi alone, do they differ, being a little longer and narrower than usual. I made a collection of the seeds of twenty- eight different kinds, and most of them were undistinguishable; when there was any difference it was excessively slight; thus, the seeds of various broccolis and cauliflowers, when seen in mass, are a little redder; those of the early green Ulm savoy are rather smaller; and those of the Breda kail slightly larger than usual, but not larger than the seeds of the wild cabbage from the coast of Wales. What a contrast in the amount of difference is presented if, on the one hand, we compare the leaves and stems of the various kinds of cabbage with their flowers, pods, and seeds, and on the other hand the corresponding parts in the varieties of maize and wheat! The explanation is obvious; the seeds alone are valued in our cereals, and their variations have been selected; whereas the seeds, seed- pods, and flowers, have been utterly neglected in the cabbage, whilst many useful variations in their leaves and stems have been noticed and preserved from an extremely remote period, for cabbages were cultivated by the old Celts. (9/67. Regnier 'De l'Economie Publique des Celtes' 1818 page 438.)

It would be useless to give a classified description (9/68. See the elder De Candolle in 'Transact. of Hort. Soc.' volume 5; and Metzger 'Kohlarten' etc.) of the numerous races, sub-races, and varieties of the cabbage; but it may be mentioned that Dr. Lindley has lately proposed (9/69. 'Gardener's Chronicle' 1859 page 992.) a system founded on the state of development of the terminal and lateral leaf-buds. Thus:

I. All the leaf-buds active and open, as in the wild-cabbage, kail, etc.

II. All the leaf-buds active, but forming heads, as in Brussel-sprouts, etc.

III. Terminal leaf-bud alone active, forming a head as in common cabbages, savoys, etc.

IV. Terminal leaf-bud alone active, and open, with most of the flowers abortive and succulent, as in the cauliflower and broccoli.

V. All the leaf-buds active and open, with most of the flowers abortive and succulent, as in the sprouting-broccoli. This latter variety is a new one, and bears the same relation to common broccoli, as Brussel-sprouts do to common cabbages; it suddenly appeared in a bed of common broccoli, and was found faithfully to transmit its newly-acquired and remarkable characters.

The principal kinds of cabbage existed at least as early as the sixteenth century (9/70. Alph. De Candolle 'Geograph. Bot.' pages 842 and 989.), so that numerous modifications of structure have been inherited for a long period. This fact is the more remarkable as great care must be taken to prevent the crossing of the different kinds. To give proof of this: I raised 233 seedlings from cabbages of different kinds, which had purposely been planted near each other, and of the seedlings no less than 155 were plainly deteriorated and mongrelised; nor were the remaining 78 all perfectly true. It may be doubted whether many permanent varieties have been formed by intentional or accidental crosses; for such crossed plants are found to be very inconstant. One kind, however, called "Cottager's Kail," has lately been produced by crossing common kail and Brussel- sprouts, recrossed with purple broccoli (9/71. 'Gardener's Chronicle' February 1858 page 128.), and is said to be true; but plants raised by me were not nearly so constant in character as any common kind of cabbage.

Although most of the kinds keep true if carefully preserved from crossing, yet the seed-beds must be yearly examined, and a few seedlings are generally found false; but even in this case the force of inheritance is shown, for, as Metzger has remarked (9/72. 'Kohlarten' s. 22.) when speaking of Brussel-sprouts, the variations generally keep to their "unter art," or main race. But in order that any kind may be truly propagated there must be no great change in the conditions of life; thus cabbages will not form heads in hot countries, and the same thing has been observed with an English variety grown during an extremely warm and damp autumn near Paris. (9/73. Godron 'De l'Espece' tome 2 page 52; Metzger 'Kohlarten' s. 22.) Extremely poor soil also affects the characters of certain varieties.

Most authors believe that all the races are descended from the wild cabbage found on the western shores of Europe; but Alph. De Candolle (9/74. 'Geograph. Bot.' page 840.) forcibly argues, on historical and other grounds, that it is more probable that two or three closely allied forms, generally ranked as distinct species, still living in the Mediterranean region, are the parents, now all commingled together, of the various cultivated kinds. In the same manner as we have often seen with domesticated animals, the supposed multiple origin of the cabbage throws no light on the characteristic differences between the cultivated forms. If our cabbages are the descendants of three or four distinct species, every trace of any sterility which may originally have existed between them is now lost, for none of the varieties can be kept distinct without scrupulous care to prevent intercrossing.

The other cultivated forms of the genus Brassica are descended, according to the view adopted by Godron and Metzger (9/75. Godron 'De l'Espece' tome 2 page 54; Metzger 'Kohlarten' s. 10.), from two species, B. napus and rapa; but according to other botanists from three species; whilst others again strongly suspect that all these forms, both wild and cultivated, ought to be ranked as a single species. Brassica napus has given rise to two large groups, namely, Swedish turnips (believed to be of hybrid origin) (9/76. 'Gardener's Chronicle and Agricult. Gazette' 1856 page 729. See more especially ibid 1868 page 275: the writer asserts that he planted a variety of cabbage (B. oleracea) close to turnips (B. rapa) and raised from the crossed seedlings true Swedish turnips. These latter plants ought, therefore, to be classed with cabbages or turnips, and not under B. napus.) and Colzas, the seeds of which yield oil. Brassica rapa (of Koch) has also given rise to two races, namely, common turnips and the oil-giving rape. The evidence is unusually clear that these latter plants, though so different in external appearance, belong to the same species; for the turnip has been observed by Koch and Godron to lose its thick roots in uncultivated soil; and when rape and turnips are sown together they cross to such a degree that scarcely a single plant comes true. (9/77. 'Gardener's Chronicle and Agricult. Gazette' 1855 page 730.) Metzger by culture converted the biennial or winter rape into the annual or summer rape,--varieties which have been thought by some authors to be specifically distinct. (9/78. Metzger, 'Kohlarten' s. 51.)

In the production of large, fleshy, turnip-like stems, we have a case of analogous variation in three forms which are generally considered as distinct species. But scarcely any modification seems so easily acquired as a succulent enlargement of the stem or root--that is, a store of nutriment laid up for the plant's own future use. We see this in our radishes, beet, and in the less generally known "turnip-rooted" celery, and in the finocchio, or Italian variety of the common fennel. Mr. Buckman has lately proved by his interesting experiments bow quickly the roots of the wild parsnip can be enlarged, as Vilmorin formerly proved in the case of the carrot. (9/79. These experiments by Vilmorin have been quoted by many writers. An eminent botanist, Prof. Decaisne, has lately expressed doubts on the subject from his own negative results, but these cannot be valued equally with positive results. On the other hand, M. Carriere has lately stated ('Gardener's Chronicle' 1865 page 1154), that he took seed from a wild carrot, growing far from any cultivated land, and even in the first generation the roots of his seedlings differed in being spindle-shaped, longer, softer, and less fibrous than those of the wild plant. From these seedlings he raised several distinct varieties.)

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."