The "London" gooseberry (which in 1852 had altogether gained 333 prizes) has, up to the present year of 1875, never reached a greater weight than that attained in 1852. Perhaps the fruit of the gooseberry has now reached the greatest possible weight, unless in the course of time some new and distinct variety shall arise.
This gradual, and on the whole steady increase of weight from the latter part of the last century to the year 1852, is probably in large part due to improved methods of cultivation, for extreme care is now taken; the branches and roots are trained, composts are made, the soil is mulched, and only a few berries are left on each bush (10/128. Mr. Saul of Lancaster in Loudon"s "Gardener"s Mag." volume 3 1828 page 421; and volume 10 1834 page 42.) but the increase no doubt is in main part due to the continued selection of seedlings which have been found to be more and more capable of yielding such extraordinary fruit. a.s.suredly the "Highwayman" in 1817 could not have produced fruit like that of the "Roaring Lion" in 1825; nor could the "Roaring Lion," though it was grown by many persons in many places, gain the supreme triumph achieved in 1852 by the "London" Gooseberry.
WALNUT (Juglans regia).
This tree and the common nut belong to a widely different order from the foregoing fruits, and are therefore here noticed. The walnut grows wild on the Caucasus and in the Himalaya, where Dr. Hooker (10/129. "Himalayan Journals" 1854 volume 2 page 334. Moorcroft "Travels" volume 2 page 146 describes four varieties cultivated in Kashmir.) found the fruit of full size, but "as hard as a hickory-nut." It has been found fossil, as M. de Saporta informs me, in the tertiary formation, of France.
In England the walnut presents considerable differences, in the shape and size of the fruit, in the thickness of the husk, and in the thinness of the sh.e.l.l; this latter quality has given rise to a variety called the thin- sh.e.l.led, which is valuable, but suffers from the attacks of t.i.tmice.
(10/130. "Gardener"s Chronicle" 1850 page 723.) The degree to which the kernel fills the sh.e.l.l varies much. In France there is a variety called the Grape or cl.u.s.ter-walnut, in which the nuts grow in "bunches of ten, fifteen, or even twenty together." There is another variety which bears on the same tree differently shaped leaves, like the heterophyllous hornbeam; this tree is also remarkable from having pendulous branches, and bearing elongated, large, thin-sh.e.l.led nuts. (10/131. Paper translated in Loudon"s "Gardener"s Mag." 1829 volume 5 page 202.) M. Cardan has minutely described (10/132. Quoted in "Gardener"s Chronicle" 1849 page 101.) some singular physiological peculiarities in the June-leafing variety, which produces its leaves and flowers four or five weeks later than the common varieties; and although in August it is apparently in exactly the same state of forwardness as the other kinds, it retains its leaves and fruit much later in the autumn. These const.i.tutional peculiarities are strictly inherited.
Lastly, walnut-trees, which are properly monoicous, sometimes entirely fail to produce male flowers. (10/133. "Gardener"s Chronicle" 1847 pages 541 and 558.)
NUTS (Corylus avellana).
Most botanists rank all the varieties under the same species, the common wild nut. (10/134. The following details are taken from the "Catalogue of Fruits, 1842 in Garden of Hort. Soc." page 103; and from Loudon"s "Encyclop. of Gardening" page 943.) The husk, or involucre, differs greatly, being extremely short in Barr"s Spanish, and extremely long in filberts, in which it is contracted so as to prevent the nut falling out.
This kind of husk also protects the nut from birds, for t.i.tmice (Parus) have been observed (10/135. "Gardener"s Chron." 1860 page 956.) to pa.s.s over filberts, and attack cobs and common nuts growing in the same orchard.
In the purple-filbert the husk is purple, and in the frizzled-filbert it is curiously laciniated; in the red-filbert the pellicle of the kernel is red.
The sh.e.l.l is thick in some varieties, but is thin in Cosford"s-nut, and in one variety is of a bluish colour. The nut itself differs much in size and shape, being ovate and compressed in filberts, nearly round and of great size in cobs and Spanish nuts, oblong and longitudinally striated in Cosford"s, and obtusely four-sided in the Downton Square nut.
CUCURBITACEOUS PLANTS.
These plants have been for a long period the opprobrium of botanists; numerous varieties have been ranked as species, and, what happens more rarely, forms which now must be considered as species have been cla.s.sed as varieties. Owing to the admirable experimental researches of a distinguished botanist, M. Naudin (10/136. "Annales des Sc. Nat. Bot." 4th series volume 6 1856 page 5.), a flood of light has recently been thrown on this group of plants. M. Naudin, during many years, observed and experimented on above 1200 living specimens, collected from all quarters of the world. Six species are now recognised in the genus Cucurbita; but three alone have been cultivated and concern us, namely, C. maxima and pepo, which include all pumpkins, gourds, squashes, and the vegetable marrow, and C. moschata. These three species are not known in a wild state; but Asa Gray (10/137. "American Journ. of Science" 2nd series volume 24 1857 page 442.) gives good reason for believing that some pumpkins are natives of N.
America.
These three species are closely allied, and have the same general habit, but their innumerable varieties can always be distinguished, according to Naudin, by certain almost fixed characters; and what is still more important, when crossed they yield no seed, or only sterile seed; whilst the varieties spontaneously intercross with the utmost freedom. Naudin insists strongly (page 15), that, though these three species have varied greatly in many characters, yet it has been in so closely an a.n.a.logous manner that the varieties can he arranged in almost parallel series, as we have seen with the forms of wheat, with the two main races of the peach, and in other cases. Though some of the varieties are inconstant in character, yet others, when grown separately under uniform conditions of life, are, as Naudin repeatedly (pages 6, 16, 35) urges, "douees d"une stabilite presque comparable a celle des especes les mieux caracterisees."
One variety, l"Orangin (pages 43, 63), has such prepotency in transmitting its character, that when crossed with other varieties a vast majority of the seedlings come true. Naudin, referring (page 47) to C. pepo, says that its races "ne different des especes veritables qu"en ce qu"elles peuvent s"allier les unes aux autres par voie d"hybridite, sans que leur descendance perde la faculte de se perpetuer." If we were to trust to external differences alone, and give up the test of sterility, a mult.i.tude of species would have to be formed out of the varieties of these three species of Cucurbita. Many naturalists at the present day lay far too little stress, in my opinion, on the test of sterility; yet it is not improbable that distinct species of plants after a long course of cultivation and variation may have their mutual sterility eliminated, as we have every reason to believe has occurred with domesticated animals. Nor, in the case of plants under cultivation, should we be justified in a.s.suming that varieties never acquire a slight degree of mutual sterility, as we shall more fully see in a future chapter when certain facts are given on the high authority of Gartner and Kolreuter. (10/138. Gartner "b.a.s.t.a.r.derzeugung" 1849 s. 87 and s. 169 with respect to Maize; on Verbasc.u.m ibid s. 92 and 181; also his "Kenntniss der Befruchtung" s. 137.
With respect to Nicotiana see Kolreuter "Zweite Forts." 1764 s. 53; though this is a somewhat different case.)
The forms of C. pepo are cla.s.sed by Naudin under seven sections, each including subordinate varieties. He considers this plant as probably the most variable in the world. The fruit of one variety (pages 33, 46) exceeds in value that of another by more than two thousand fold! When the fruit is of very large size, the number produced is few (page 45); when of small size, many are produced. No less astonishing (page 33) is the variation in the shape of the fruit, the typical form apparently is egg-like, but this becomes either drawn out into a cylinder, or shortened into a flat disc. We have also an almost infinite diversity in the colour and state of surface of the fruit, in the hardness both of the sh.e.l.l and of the flesh, and in the taste of the flesh, which is either extremely sweet, farinaceous, or slightly bitter. The seeds also differ in a slight degree in shape, and wonderfully in size (page 34), namely, from six or seven to more than twenty-five millimetres in length.
In the varieties which grow upright or do not run and climb, the tendrils, though useless (page 31), are either present or are represented by various semi-monstrous organs, or are quite absent. The tendrils are even absent in some running varieties in which the stems are much elongated. It is a singular fact that (page 31) in all the varieties with dwarfed stems, the leaves closely resemble each other in shape.]
Those naturalists who believe in the immutability of species often maintain that, even in the most variable forms, the characters which they consider of specific value are unchangeable. To give an example from a conscientious writer (10/139. G.o.dron "De l"Espece" tome 2 page 64.) who, relying on the labours of M. Naudin, and referring to the species of Cucurbita, says, "au milieu de toutes les variations du fruit, les tiges, les feuilles, les calices, les corolles, les etamines restent invariables dans chacune d"elles." Yet M. Naudin, in describing Cucurbita pepo (page 30), says, "Ici, d"ailleurs, ce ne sont pas seulement les fruits qui varient, c"est aussi le feuillage et tout le port de la plante. Neanmoins, je crois qu"on la distinguera toujours facilement des deux autres especes, si l"on veut ne pas perdre de vue les caracteres differentiels que je m"efforce de faire ressortir. Ces caracteres sont quelquefois peu marques: il arrive meme que plusieurs d"entre eux s"effacent presque entierement, mais ii en reste toujours quelques-uns qui remettent l"observateur sur la voie." Now let it be noted what a difference, with regard to the immutability of the so- called specific characters this paragraph produces on the mind, from that above quoted from M. G.o.dron.
I will add another remark: naturalists continually a.s.sert that no important organ varies; but in saying this they unconsciously argue in a vicious circle; for if an organ, let it be what it may, is highly variable, it is regarded as unimportant, and under a systematic point of view this is quite correct. But as long as constancy is thus taken as the criterion of importance, it will indeed be long before an important organ can be shown to be inconstant. The enlarged form of the stigmas, and their sessile position on the summit of the ovary, must be considered as important characters, and were used by Gasparini to separate certain pumpkins as a DISTINCT GENUS; but Naudin says (page 20), these parts have no constancy, and in the flowers of the Turban varieties of C. maxima they sometimes resume their ordinary structure. Again, in C. maxima, the carpels (page 19) which form the turban project even as much as two-thirds of their length out of the receptacle, and this latter part is thus reduced to a sort of platform; but this remarkable structure occurs only in certain varieties, and graduates into the common form in which the carpels are almost entirely enveloped within the receptacle. In C. moschata the ovarium (page 50) varies greatly in shape, being oval, nearly spherical, or cylindrical, more or less swollen in the upper part, or constricted round the middle, and either straight or curved. When the ovarium is short and oval the interior structure does not differ from that of C. maxima and pepo, but when it is elongated the carpels occupy only the terminal and swollen portion. I may add that in one variety of the cuc.u.mber (Cuc.u.mis sativus) the fruit regularly contains five carpels instead of three. (10/140. Naudin "Annal.
des Sc. Nat." 4th series Bot. tome 11 1859 page 28.) I presume that it will not be disputed that we here have instances of great variability in organs of the highest physiological importance, and with most plants of the highest cla.s.sificatory importance.
[Sageret (10/141. "Memoire sur les Cucurbitacees" 1826 pages 6, 24.) and Naudin found that the cuc.u.mber (C. sativus) could not be crossed with any other species of the genus; therefore no doubt it is specifically distinct from the melon. This will appear to most persons a superfluous statement; yet we hear from Naudin (10/142. "Flore des Serres" October 1861 quoted in "Gardener"s Chronicle" 1861 page 1135. I have often consulted and taken some facts from M. Naudin"s Memoir on Cuc.u.mis in "Annal. des Sc. Nat." 4th series Bot. tome 11 1859 page 5.) that there is a race of melons, in which the fruit is so like that of the cuc.u.mber, "both externally and internally, that it is hardly possible to distinguish the one from the other except by the leaves." The varieties of the melon seem to be endless, for Naudin after six years" study had not come to the end of them: he divides them into ten sections, including numerous sub-varieties which all intercross with perfect ease. (10/143. See also Sageret "Memoire" page 7.) Of the forms considered by Naudin to be varieties, botanists have made thirty distinct species! "and they had not the slightest acquaintance with the mult.i.tude of new forms which have appeared since their time." Nor is the creation of so many species at all surprising when we consider how strictly their characters are transmitted by seed, and how wonderfully they differ in appearance: "Mira est quidem foliorum et habitus diversitas, sed multo magis fructuum," says Naudin. The fruit is the valuable part, and this, in accordance with the common rule, is the most modified part. Some melons are only as large as small plums, others weigh as much as sixty-six pounds. One variety has a scarlet fruit! Another is not more than an inch in diameter, but sometimes more than a yard in length, "twisting about in all directions like a serpent." It is a singular fact that in this latter variety many parts of the plant, namely, the stems, the footstalks of the female flowers, the middle lobe of the leaves, and especially the ovarium, as well as the mature fruit, all show a strong tendency to become elongated.
Several varieties of the melon are interesting from a.s.suming the characteristic features of distinct species and even of distinct though allied genera: thus the serpent-melon has some resemblance to the fruit of Trichosanthes anguina; we have seen that other varieties closely resemble cuc.u.mbers; some Egyptian varieties have their seeds attached to a portion of the pulp, and this is characteristic of certain wild forms. Lastly, a variety of melon from Algiers is remarkable from announcing its maturity by "a spontaneous and almost sudden dislocation," when deep cracks suddenly appear, and the fruit falls to pieces; and this occurs with the wild C.
momordica. Finally, M. Naudin well remarks that this "extraordinary production of races and varieties by a single species and their permanence when not interfered with by crossing, are phenomena well calculated to cause reflection."
USEFUL AND ORNAMENTAL TREES.
Trees deserve a pa.s.sing notice on account of the numerous varieties which they present, differing in their precocity, in their manner of growth, their foliage, and bark. Thus of the common ash (Fraxinus excelsior) the catalogue of Messrs. Lawson of Edinburgh includes twenty-one varieties, some of which differ much in their bark; there is a yellow, a streaked reddish-white, a purple, a wart-barked and a fungous-barked variety.
(10/144. Loudon"s "Arboretum et Fruticetum" volume 2 page 1217.) Of hollies no less than eighty-four varieties are grown alongside each other in Mr.
Paul"s nursery. (10/145. "Gardener"s Chronicle" 1866 page 1096.) In the case of trees, all the recorded varieties, as far as I can find out, have been suddenly produced by one single act of variation. The length of time required to raise many generations, and the little value set on the fanciful varieties, explains how it is that successive modifications have not been acc.u.mulated by selection; hence, also, it follows that we do not here meet with sub-varieties subordinate to varieties, and these again subordinate to higher groups. On the Continent, however, where the forests are more carefully attended to than in England, Alph. De Candolle (10/146.
"Geograph. Bot." page 1096.) says that there is not a forester who does not search for seeds from that variety which he esteems the most valuable.
Our useful trees have seldom been exposed to any great change of conditions; they have not been richly manured, and the English kinds grow under their proper climate. Yet in examining extensive beds of seedlings in nursery-gardens considerable differences may be generally observed in them; and whilst touring in England I have been surprised at the amount of difference in the appearance of the same species in our hedgerows and woods. But as plants vary so much in a truly wild state, it would be difficult for even a skilful botanist to p.r.o.nounce whether, as I believe to be the case, hedgerow trees vary more than those growing in a primeval forest. Trees when planted by man in woods or hedges do not grow where they would naturally be able to hold their place against a host of compet.i.tors, and are therefore exposed to conditions not strictly natural: even this slight change would probably suffice to cause seedlings raised from such trees to be variable. Whether or not our half-wild English trees, as a general rule, are more variable than trees growing in their native forests, there can hardly be a doubt that they have yielded a greater number of strongly-marked and singular variations of structure.
In manner of growth, we have weeping or pendulous varieties of the willow, ash, elm, oak, and yew, and other trees; and this weeping habit is sometimes inherited, though in a singularly capricious manner. In the Lombardy poplar, and in certain fastigiate or pyramidal varieties of thorns, junipers, oaks, etc., we have an opposite kind of growth. The Hessian oak (10/147. "Gardener"s Chronicle" 1842 page 36.), which is famous from its fastigiate habit and size, bears hardly any resemblance in general appearance to a common oak; "its acorns are not sure to produce plants of the same habit; some, however, turn out the same as the parent-tree."
Another fastigiate oak is said to have been found wild in the Pyrenees, and this is a surprising circ.u.mstance; it generally comes so true by seed, that De Candolle considered it as specifically distinct. (10/148. Loudon"s "Arboretum et Fruticetum" volume 3 page 1731.) The fastigiate Juniper (J.
suecica) likewise transmits its character by seed. (10/149. Ibid volume 4 page 2489.) Dr. Falconer informs me that in the Botanic Gardens at Calcutta the great heat caused apple-trees to become fastigiate; and we thus see the same result following from the effects of climate and from some unknown cause. (10/150. G.o.dron "De l"Espece" tome 2 page 91 describes four varieties of Robinia remarkable from their manner of growth.)
In foliage we have variegated leaves which are often inherited; dark purple or red leaves, as in the hazel, barberry, and beech, the colour in these two latter trees being sometimes strongly and sometimes weakly inherited (10/151. "Journal of a Horticultural Tour, by Caledonian Hort. Soc." 1823 page 107. Alph. De Candolle "Geograph. Bot." page 1083. Verlot "Sur La Production des Varietes" 1865 page 55 for the Barberry.); deeply-cut leaves; and leaves covered with p.r.i.c.kles, as in the variety of the holly well called ferox, which is said to reproduce itself by seed. (10/152.
Loudon"s "Arboretum et Fruticetum" volume 2 page 508.) In fact, nearly all the peculiar varieties evince a tendency, more or less strongly marked, to reproduce themselves by seed. (10/153. Verlot "Des Varietes" 1865 page 92.) This is to a certain extent the case, according to Bosc (10/154. Loudon"s "Arboretum et Fruticetum" volume 3 page 1376.), with three varieties of the elm, namely, the broad-leafed, lime-leafed, and twisted elm, in which latter the fibres of the wood are twisted. Even with the heterophyllous hornbeam (Carpinus betulus), which bears on each twig leaves of two shapes, "several plants raised from seed all retained "the same peculiarity."
(10/155. "Gardener"s Chronicle" 1841 page 687.) I will add only one other remarkable case of variation in foliage, namely, the occurrence of two sub- varieties of the ash with simple instead of pinnated leaves, and which generally transmit their character by seed. (10/156. G.o.dron "De l"Espece"
tome 2 page 89. In Loudon"s "Gardener"s Mag." volume 12 1836 page 371, a variegated bushy ash is described and figured, as having simple leaves; it originated in Ireland.) The occurrence, in trees belonging to widely different orders, of weeping and fastigiate varieties, and of trees bearing deeply cut, variegated, and purple leaves, shows that these deviations of structure must result from some very general physiological laws.
Differences in general appearance and foliage, not more strongly marked than those above indicated, have led good observers to rank as distinct species certain forms which are now known to be mere varieties. Thus, a plane-tree long cultivated in England was considered by almost every one as a North American species: but is now ascertained by old records, as I am informed by Dr. Hooker, to be a variety. So, again, the Thuja pendula or filiformis was ranked by such good observers as Lambert, Wallich, and others, as a true species; but it is now known that the original plants, five in number, suddenly appeared in a bed of seedlings, raised at Mr.
Loddige"s nursery, from T. orientalis; and Dr. Hooker has adduced excellent evidence that at Turin seeds of T. pendula have reproduced the parent form, T. orientalis. (10/157. "Gardener"s Chronicle" 1863 page 575.)
Every one must have noticed how certain individual trees regularly put forth and shed their leaves earlier or later than others of the same species. There is a famous horse-chestnut in the Tuileries which is named from leafing so much earlier than the others. There is also an oak near Edinburgh which retains its leaves to a very late period. These differences have been attributed by some authors to the nature of the soil in which the trees grow; but Archbishop Whately grafted an early thorn on a late one, and vice versa, and both grafts kept to their proper periods, which differed by about a fortnight, as if they still grew on their own stocks.
(10/158. Quoted from Royal Irish Academy in "Gardener"s Chronicle" 1841 page 767.) There is a Cornish variety of the elm which is almost an evergreen, and is so tender that the shoots are often killed by the frost; and the varieties of the Turkish oak (Q. cerris) may be arranged as deciduous, sub-evergreen, and evergreen. (10/159. Loudon "Arboretum et Fruticetum:" for Elm see volume 3 page 1376; for Oak page 1846.)
SCOTCH FIR (Pinus sylvestris).
I allude to this tree as it bears on the question of the greater variability of our hedgerow trees compared with those under strictly natural conditions. A well-informed writer (10/160. "Gardener"s Chronicle"
1849?, page 822.) states that the Scotch fir presents few varieties in its native Scotch forests; but that it "varies much in figure and foliage, and in the size, shape, and colour of its cones, when several generations have been produced away from its native locality." There is little doubt that the highland and lowland varieties differ in the value of their timber, and that they can be propagated truly by seed; thus justifying Loudon"s remark, that "a variety is often of as much importance as a species, and sometimes far more so." (10/161. "Arboretum et Fruticetum" volume 4 page 2150.) I may mention one rather important point in which this tree occasionally varies; in the cla.s.sification of the Coniferae, sections are founded on whether two, three, or five leaves are included in the same sheath; the Scotch fir has properly only two leaves thus enclosed, but specimens have been observed with groups of three leaves in a sheath. (10/162. "Gardener"s Chronicle" 1852 page 693.) Besides these differences in the semi-cultivated Scotch fir, there are in several parts of Europe natural or geographical races, which have been ranked by some authors as distinct species. (10/163.
See "Beitrage zur Kenntniss Europaischer Pinus-arten von Dr. Christ: Flora, 1864." He shows that in the Ober-Engadin P. sylvestris and montana are connected by intermediate links.) Loudon (10/164. "Arboretum et Fruticetum"
volume 4 pages 2159 and 2189.) considers P. pumilio, with its several sub- varieties, as mughus, nana, etc., which differ much when planted in different soils, and only come "tolerably true from seed," as alpine varieties of the Scotch fir; if this were proved to be the case, it would be an interesting fact as showing that dwarfing from long exposure to a severe climate is to a certain extent inherited.
THE HAWTHORN (Crataegus oxyacantha).
The Hawthorn has varied much. Besides endless slighter variations in the form of the leaves, and in the size, hardness, fleshiness, and shape of the berries, Loudon (10/165. Ibid volume 2 page 830; Loudon"s "Gardener"s Mag."
volume 6 1830 page 714.) enumerates twenty-nine well-marked varieties.
Besides those cultivated for their pretty flowers, there are others with golden-yellow, black, and whitish berries; others with woolly berries, and others with re-curved thorns. Loudon truly remarks that the chief reason why the hawthorn has yielded more varieties than most other trees, is that nurserymen select any remarkable variety out of the immense beds of seedlings which are annually raised for making hedges. The flowers of the hawthorn usually include from one to three pistils; but in two varieties, named monogyna and sibirica, there is only a single pistil; and d"a.s.so states that the common thorn in Spain is constantly in this state. (10/166.
Loudon"s "Arboretum et Fruticetum" volume 2 page 834.) There is also a variety which is apetalous, or has its petals reduced to mere rudiments.
The famous Glas...o...b..ry thorn flowers and leafs towards the end of December, at which time it bears berries produced from an earlier crop of flowers.
(10/167. Loudon"s "Gardener"s Mag." volume 9 1833 page 123.) It is worth notice that several varieties of the hawthorn, as well as of the lime and juniper, are very distinct in their foliage and habit whilst young, but in the course of thirty or forty years become extremely like each other (10/168. Ibid volume 11 1835 page 503.) thus reminding us of the well-known fact that the deodar, the cedar of Lebanon, and that of the Atlas, are distinguished with the greatest ease whilst young, but with difficulty when old.
FLOWERS.
I shall not for several reasons treat the variability of plants which are cultivated for their flowers alone at any great length. Many of our favourite kinds in their present state are the descendants of two or more species crossed and commingled together, and this circ.u.mstance alone would render it difficult to detect the difference due to variation. For instance, our Roses, Petunias, Calceolarias, Fuchsias, Verbenas, Gladioli, Pelargoniums, etc., certainly have had a multiple origin. A botanist well acquainted with the parent-forms would probably detect some curious structural differences in their crossed and cultivated descendant; and he would certainly observe many new and remarkable const.i.tutional peculiarities. I will give a few instances, all relating to the Pelargonium, and taken chiefly from Mr. Beck (10/169. "Gardener"s Chronicle" 1845 page 623.) a famous cultivator of this plant: some varieties require more water than others; some are "very impatient of the knife if too greedily used in making cuttings;" some, when potted, scarcely "show a root at the outside of the ball of the earth;" one variety requires a certain amount of confinement in the pot to make it throw up a flower- stem; some varieties bloom well at the commencement of the season, others at the close; one variety is known (10/170. D. Beaton in "Cottage Gardener"
1860 page 377. See also Mr. Beck on the habits of Queen Mab in "Gardener"s Chronicle" 1845 page 226.), which will stand "even pine-apple top and bottom heat, without looking any more drawn than if it had stood in a common greenhouse; and Blanche Fleur seems as if made on purpose for growing in winter, like many bulbs, and to rest all summer." These odd const.i.tutional peculiarities would enable a plant in a state of nature to become adapted to widely different circ.u.mstances and climates.
Flowers possess little interest under our present point of view, because they have been almost exclusively attended to and selected for their beautiful colour, size, perfect outline, and manner of growth. In these particulars hardly one long-cultivated flower can be named which has not varied greatly. What does a florist care for the shape and structure of the organs of fructification, unless, indeed, they add to the beauty of the flower? When this is the case, flowers become modified in important points; stamens and pistils may be converted into petals, and additional petals may be developed, as in all double flowers. The process of gradual selection by which flowers have been rendered more and more double, each step in the process of conversion being inherited, has been recorded in several instances. In the so-called double flowers of the Compositae, the corollas of the central florets are greatly modified, and the modifications are likewise inherited. In the columbine (Aquilegia vulgaris) some of the stamens are converted into petals having the shape of nectaries, one neatly fitting into the other; but in one variety they are converted into simple petals. (10/171. Moquin-Tandon "Elements de Teratologie" 1841 page 213.) In the "hose in hose" primulae, the calyx becomes brightly coloured and enlarged so as to resemble a corolla; and Mr. W. Wooler informs me that this peculiarity is transmitted; for he crossed a common polyanthus with one having a coloured calyx (10/172. See also "Cottage Gardener" 1860 page 133.) and some of the seedlings inherited the coloured calyx during at least six generations. In the "hen-and-chicken" daisy the main flower is surrounded by a brood of small flowers developed from buds in the axils of the scales of the involucre. A wonderful poppy has been described, in which the stamens are converted into pistils; and so strictly was this peculiarity inherited that, out of 154 seedlings, one alone reverted to the ordinary and common type. (10/173. Quoted by Alph. de Candolle "Bibl.
Univ." November 1862 page 58.) Of the c.o.c.k"s-comb (Celosia cristata), which is an annual, there are several races in which the flower-stem is wonderfully "fasciated" or compressed; and one has been exhibited (10/174.
Knight "Transact. Hort. Soc." volume 4 page 322.) actually eighteen inches in breadth. Peloric races of Gloxinia speciosa and Antirrhinum majus can be propagated by seed, and they differ in a wonderful manner from the typical form both in structure and appearance.
A much more remarkable modification has been recorded by Sir William and Dr. Hooker (10/175. "Botanical Magazine" tab. 5160 figure 4; Dr. Hooker in "Gardener"s Chronicle" 1860 page 190; Prof. Harvey in "Gardener"s Chronicle" 1860 page 145; Mr. Crocker in "Gardener"s Chron." 1861 page 1092.) in Begonia frigida. This plant properly produces male and female flowers on the same fascicles; and in the female flowers the perianth is superior; but a plant at Kew produced, besides the ordinary flowers, others which graduated towards a perfect hermaphrodite structure; and in these flowers the perianth was inferior. To show the importance of this modification under a cla.s.sificatory point of view, I may quote what Prof.
Harvey says, namely, that had it "occurred in a state of nature, and had a botanist collected a plant with such flowers, he would not only have placed it in a distinct genus from Begonia, but would probably have considered it as the type of a new natural order." This modification cannot in one sense be considered as a monstrosity, for a.n.a.logous structures naturally occur in other orders, as with Saxifragae and Aristolochiaceae. The interest of the case is largely added to by Mr. C.W. Crocker"s observation that seedlings from the NORMAL flowers produced plants which bore, in about the same proportion as the parent-plant, hermaphrodite flowers having inferior perianths. The hermaphrodite flowers fertilised with their own pollen were sterile.
If florists had attended to, selected, and propagated by seed other modifications of structure besides those which are beautiful, a host of curious varieties would certainly have been raised; and they would probably have transmitted their characters so truly that the cultivator would have felt aggrieved, as in the case of culinary vegetables, if his whole bed had not presented a uniform appearance. Florists have attended in some instances to the leaves of their plant, and have thus produced the most elegant and symmetrical patterns of white, red, and green, which, as in the case of the pelargonium, are sometimes strictly inherited. (10/176. Alph.
de Candolle "Geograph. Bot." page 1083; "Gardener"s Chronicle" 1861 page 433. The inheritance of the white and golden zones in Pelargonium largely depends on the nature of the soil. See D. Beaton in "Journal of Horticulture" 1861 page 64.) Any one who will habitually examine highly- cultivated flowers in gardens and greenhouses will observe numerous deviations in structure; but most of these must be ranked as mere monstrosities, and are only so far interesting as showing how plastic the organisation becomes under high cultivation. From this point of view such works as Professor Moquin-Tandon"s "Teratologie" are highly instructive.
ROSES.
These flowers offer an instance of a number of forms generally ranked as species, namely, R. centifolia, gallica, alba, damascena, spinosissima, bracteata, indica, semperflorens, moschata, etc., which have largely varied and been intercrossed. The genus Rosa is a notoriously difficult one, and, though some of the above forms are admitted by all botanists to be distinct species, others are doubtful; thus, with respect to the British forms, Babington makes seventeen, and Bentham only five species. The hybrids from some of the most distinct forms--for instance, from R. indica, fertilised by the pollen of R. centifolia--produce an abundance of seed; I state this on the authority of Mr. Rivers (10/177. "Rose Amateur"s Guide" T. Rivers 1837 page 21.) from whose work I have drawn most of the following statements. As almost all the aboriginal forms brought from different countries have been crossed and re-crossed, it is no wonder that Targioni- Tozzetti, in speaking of the common roses of the Italian gardens, remarks that "the native country and precise form of the wild type of most of them are involved in much uncertainty." (10/178. "Journal Hort. Soc." volume 9 1855 page 182.) Nevertheless, Mr. Rivers in referring to R. indica (page 68) says that the descendants of each group may generally be recognised by a close observer. The same author often speaks of roses as having been a little hybridised; but it is evident that in very many cases the differences due to variation and to hybridisation can now only be conjecturally distinguished.