FOOTNOTES:

FOOTNOTES:[66]'Bull. Acad. Belg.,' t. xix, part iii, 1852, p. 315.

[66]'Bull. Acad. Belg.,' t. xix, part iii, 1852, p. 315.

When an organ becomes divided it receives at the hands of descriptive botanists the appellations cleft, partite, or sect, according to the depth of the division; hence in considering the teratological instances of this nature, the term fission has suggested itself as an appropriate one to be applied to the subdivision of an habitually entire or undivided organ. It thus corresponds pretty nearly in its application with the term Chorisisor "dédoublement," or with the "disjonctions qui divisent les organes" of Moquin-Tandon.[67]It is usually, but not always, a concomitant with hypertrophy, and dependent on luxuriance of growth.

It must be understood therefore that the term, as generally applied, does not so much indicate the cleavage of a persistent organ, as it does the formation and development of two or more growing points instead of one, whence results a branching or forking (di-tri-chotomy) of the affected organ. In some instances it seems rather to be due to the relative deficiency of cellular, as contrasted with fibro-vascular tissue.

Fission of axile organs.—This condition is scarcely to be distinguished from multiplication of the axile organs (which see). A little attention, however, will generally show whether the unusual number of branches is a consequence of the development of a large number of distinct shoots, as happens, for instance, when a tree is pollarded, or of a division of one. M. Fournier[68]gives as an illustration the case of a specimen ofRuscus aculeatusin which there occurred a division of the foliaceous branches into two segments, reaching as far as the insertion of the flower, but no further. He also mentions lateral cleavage effected by a notching of the margin, the notch being anterior to the flowers and always directed towards their insertion. In the allied genusDanaë, Webb, 'Phyt. Canar.,'p. 320, describes the fascicles of flowers as in "crenulis brevibus ad marginem ramulorum dispositis." Sometimes, on the other hand,Danaëhas a fascicle of flowers inserted on the middle of the upper surface, as inRuscus. Wigand mentions an instance inDigitalis lutea, where the upper part of the stem was divided into six or seven racemes; possibly this was a case of fasciation, but such a division of the inflorescence is by no means uncommon in the spicate species ofVeronica. I havealso seen it inPlantago lanceolata,Reseda luteola,Campanula medium,Epacris impressa, and a bifurcation of the axis of the spikelet within the outer glumes inLolium perenne[69]andAnthoxanthum odoratum. In the Kew Museum is preserved a cone ofAbies excelsa,[70]dividing into two divisions, each bearing bracts and scales. A similar thing frequently occurs in the male catkins ofCedrus Libani(fig. 25).

Fig. 25.—Bifurcated male inflorescence,Cedrus Libani.

This subdivision of axial organs is not unfrequently the result of some injury or mutilation, thus Duval Jouve alludes to the frequency with which branched stems are produced in the various species ofEquisetum, as a consequence of injuries to the main stem, but this is rather to be considered as a multiplication of parts than as a subdivision of one.

Fig.26.—Bifurcated leaf ofLamium album, &c.

Fission of foliar organs.—Many leaves exhibit constantly the process of fission, such as theSalisburia adiantifolia, and which is due perhaps as much to the absence or relatively small proportion of cellular as compared with vascular tissue, as to absolute fission. In the same way we have laciniated leaves of the Persian lilac,Syringa persica, and Moquin mentions instances in a species ofMercurialisin which the leaves were deeply slashed. InChenopodium Quinoathe leaves were so numerous and the clefts so deep, that the species was hardly recognisable, while on a branch ofRhus Cotinusobserved by De Candolle the lobes were so narrow and so fine as to give the plant the aspect of anUmbellifer. Wigand ('Flora,' 1856, p. 706) speaks of the leaves ofDipsacus fullonumwith bi-partite leaves; Moquin mentions the occurrence of a leaf of an oleander bi-lobed at the summit, so as to give the appearance of a fusion of two leaves. Steinheil has recorded an instance inScabiosa atropurpureain which one of the stem leaves presented the following peculiarities. It was simple below, but divided above into two equal lobes, provided each with a median nerve.[71]Steinheil has also recorded aCerastiumin which one of the leaves was provided with two midribs; above this leaf was a group of ternate leaves. I have seen similar instances in the common Elm,Ulmus campestris, and also in the common nettle,Urtica dioica,the leaves of which latter thus resembled those ofUrtica biloba, which are habitually bilobed at the summit. M. Clos[72]mentions an instance where the terminal leaf and first bract ofOrchis sambucinawere divided into two segments. The same author also mentions the leaves ofAnemiopsis californica, which were divided in their upper halves each into two lobes—also leaves of a lentil springing from a fasciated stem and completely divided into two segments, but with only a single bud in the axil. The axillary branches in like manner showed traces of cleavage. Fig. 26 represents a case of this kind inLamium album, conjoined with suppression of the flowers on one side of the stem. I have also in my herbarium a leaf ofArum maculatum, with a stalk single at the base, but dividing into two separate stalks, each bearing a hastate lamina, the form of which is so perfect that were it not from the venation of the sheath it would be considered that there was here a union of two leaves rather than a bifurcation of one. A garden Pelargonium presented the same appearance.

Fig.27.—Bifurcated leaf ofPelargonium.

Fern fronds are particularly liable to this kind of subdivision, and they exhibit it in almost every degree, from a simple bifurcation of the frond to the formation of large tufts of small lobes all formed on the same plan by the repeated forking of the pinnules. These may be considered as cases of hypertrophy.

Moquin-Tandon, at a meeting of the Botanical Societyof France (April 3rd, 1858) exhibited a leaf ofCerasus Lauro-Cerasusdivided in such a manner as to resemble a leaf ofCitrusor ofPhyllarthron. In this case, therefore, the disunion must have taken place laterally, and not from apex towards base, as is most common. The leaves of the common horse-radish,Cochlearia Armoracia, are very subject to this pinnated subdivision of the margin, and numerous other illustrations might be given.

Fig.28.—Bifurcated frond,Scolopendrium vulgare.

A. Braun describes a singular case in a leaf ofIrinaglabrawherein the blade of the leaf on one side was deeply and irregularly laciniated, the other side remaining entire. (Verhandl., d. 35,Naturforscherversammlung, tab. 3.) Laciniate varieties of plants are of frequent occurrence in gardens where they are often cultivated for their beauty or singularity; thus, there are laciniated alders, fern-leaved beeches and limes, oak-leaved laburnums, &c. A list of several of these is subjoined. A similar fission takes place constantly in the cotyledons of some plants, sometimes, as inConiferæ, to such an extent as to give an appearance as if there were several cotyledons.[73]

It is not always easy to recognise, at a first glance, whether the division be the result of disunion or of an incomplete union of two leaves, but we may be guided by the number of leaves in the cycle or the whorl. The number is complete in cases of partial disjunction, while in cases of fusion it is incomplete. Again, in instances of disjunction, there is only one point of origin, but, when two leaves are grafted together, two such points may generally be detected at the base of the leaf, or a transverse section of the leaf-stalk will show indications of fusion. The number and position of the midribs will also serve as a guide, as in cases of fusion there are generally two or more midribs, according to the number of fused leaves; but as Moquin well remarks, this latter character cannot be always depended upon, for the median nerve may divide without any corresponding separation of the cellular portions of the leaf. The author just quoted cites examples of this kind inCardamine pratensis,Hedera Helix,Plantago major,Geranium nodosum.

The following list of plants commonly producing leaves that are cleft or divided, to a greater extent than is usual in the species, is mainly taken from one given by Schlechtendal, 'Bot. Zeit.,' 1844, p. 441, with additions from other sources. The ! indicates that the author has himself met with the deviation inquestion. Many are cultivated as garden varieties under the names here given.

Trollius europæus dissectus.Chelidonium majus laciniatum!Glaucium luteum.Brassica oleracea!Tilia parvifolia laciniata.asplenifolia!Acer platanoides laciniatum.crispum.Æsculus Hippocastanum incisum!asplenifolium.Vitis vinifera apiifolia!laciniosa.Ilex Aquifolium!Rhus Toxicodendron quercifolium.Cotinus.Ervum Lens.Cytisus Laburnum quercifolium!incisum.Rubus fraticosus laciniatus!Pyrcis communis.Cerasus Lauro-cerasus.Apium graveolens!Pimpinella magna.Saxifraga.Cratægus Oxyacantha laciniata.quercifolia!Ribes nigrum.Sambucus nigra laciniata!racemosa laciniata.Dipsacus fullonum.Scabiosa atropurpurea!Symphoricarpus racemosus.Helianthus sp.!Lonicera Periclymenum quercifolia!Syringa persica laciniata!Syringa vulgaris!Nerium Oleander!Lamium purpureum.album!Salvia officinalis.Solanum Dulcamara!Fraxinus excelsior crispa.Veronica austriaca.Polemonium cæruleum.Juglans regia laciniata!heterophylla.filicifolia.Anemiopsis californica.Chenopodium Quinoa.Ulmus americana incisa.Fagus sylvatica heterophylla!laciniata!aspleniifolia!incisa.salicifolia!Mercurialis perennis.Urtica dioica.Quercus Cerris laciniata!pubescens filicina.Betula populifolia laciniata.alba dalecarlica.Alnus incana laciniata!glutinosa laciniata!quercifolia.oxyacanthifolia.Corylus Avellana heterophylla!laciniata!urticifolia.Carpinus Betulus incisa!quercifolia.heterophylla.Castanea vesca heterophylla.quercifolia.incisa.Populus alba acerifolia.palmata.quercifolia.balsamifera.Orchis sambucina.Arum maculatum.Filices sp. pl.

See also Schlechtendal, 'Bot. Zeit.,' tom. xiii, p. 823. A. Braun, loc. supra citat. For Ferns too numerous for insertion, see Moore, 'Nature-Printed Ferns,' 8vo ed., 2 vols. Clos, 'Mém. Acad. Toulouse,' 1862, p. 51.

Fission of the petals, &c.—The floral leaves are subject to a similar process of cleavage to that which has justbeen mentioned as taking place in the leaves. This, indeed, occurs very often as a normal occurrence as in the petals of mignonette (Reseda), or those ofAlsine mediaand many other plants. Here, however, we have only to allude to those instances in which the cleavage occurs in flowers whose sepals or petals are usually entire. Under this category Moquin mentions a petal ofBrassica oleraceacompletely split into two. Linné in his 'Flora Lapponica' (pp. 145 and 164) mentions quadrifid petals ofLychnis dioica, and much divided petals ofRubus arcticus. Among other plants subject to this division of sepals or petals may be mentioned as having come within the writer's personal observation,Ranunculus Lingua,R. acris,Papaver somniferum, and others of this genus,Saponaria sp.,Dianthus,Narcissus, &c.

In some of the garden varieties ofCyclamenthe corolla looks at first sight as if double, and the plan of the flower is oblong or elliptical, instead of circular. In these flowers each lobe of the corolla is divided almost to the base into two lobes, so that there appear to be ten lobes to the corolla instead of five, as usual. The stamens are normal in form and number in these flowers.

In the paroquet tulips of gardeners the segments of the perianth are deeply and irregularly gashed, the segments occasionally becoming rolled up and their margins coherent so as to form little tubular spurs. I have also noticed the segments of the perianth inCrocusandColchicumdeeply cleft, so much so sometimes, as to equal in this particular the stigmas. In the flowers of a species ofOncidium, communicated to me by Mr. Currey, the lip was divided into three segments perfectly distinct one from the other, but confluent with the column; the two side pieces had callosities at the upper edge close to the base, the central piece had a similar wartlike process in its centre. In these flowers the ovary, the stigma, and the anther were all in a rudimentary condition. Some verbenas raised by Mr.Wills offer a curious illustration of this condition. It will be remembered that some of the lobes or petals of a verbena are normally divided at the base to a slight degree, but in the flowers in question this is carried to such an extent that the enlarged lobes are pushed into the centre of the flower and simulate, at a first glance, a distinct and separate organ, though in reality it is but an enlargement of what occurs normally.[74]

Fig.29.—Flower ofOncidium sp.seen from the back. The lip is divided into three unequal segments.

Moquin mentions having seen the stamens ofMatthiola incanaandSilene conicacompletely divided, each section bearing half an anther, exactly as happens inPolygalaceæ. In tulips and lilies the same author mentions division of the anther only, the filament remaining entire, as happens naturally in many species ofVaccinium.

A division of the individual carpels occurs very frequently when those organs become more or less leafy, as inTrifolium repens, and other plants to be hereafter mentioned.

The instances given in this chapter have all been cases wherein the division or the accessory growth has taken place in one plane only and that planethe same as that of the affected organ, but there are other examples, probably equally due to fissiparous division, where the new growth is either parallel to, or even at angle with the primary organ. Of such nature are some of those instances wherein two leaves appear to be placed back to back. These partake of the nature of excrescences or of exaggerated developments, and hence will be more fully treated of under the head of hypertrophy. It must be remembered that in some of these cases the fission may be a resumption of characters proper to the species under natural conditions, but lost by cultivation or otherwise. Thus, Mr. Buckman accounts for "finger-and-toe" in root-crops on the principle of reversion to the wild form.

FOOTNOTES:[67]Loc. cit., p. 295.[68]'Bull. Soc. Bot. France,' 1857, p. 758.[69]Masters, 'Jourl. Linn. Soc.,' vol. vii, p. 121.[70]Cramer, 'Bildungsabweichungen,' p. 4, tab. vi, fig. 4, figures a case of the same kind inPinus Cembra.[71]'Ann. des Science Nat.,' 2nd series, t. iv, p. 147, tab. v, figs. 3 and 4.[72]'Mém. Acad. Scien. Toulouse,' 5th series, vol. iii.[73]Duchartre, 'Ann. Sc. Nat.,' 3rd series, 1848, vol. x, p. 207.[74]Masters, 'Rep. Bot. Congress,' London, 1866, p. 136, tab. 7, f. 15, 16.

[67]Loc. cit., p. 295.

[68]'Bull. Soc. Bot. France,' 1857, p. 758.

[69]Masters, 'Jourl. Linn. Soc.,' vol. vii, p. 121.

[70]Cramer, 'Bildungsabweichungen,' p. 4, tab. vi, fig. 4, figures a case of the same kind inPinus Cembra.

[71]'Ann. des Science Nat.,' 2nd series, t. iv, p. 147, tab. v, figs. 3 and 4.

[72]'Mém. Acad. Scien. Toulouse,' 5th series, vol. iii.

[73]Duchartre, 'Ann. Sc. Nat.,' 3rd series, 1848, vol. x, p. 207.

[74]Masters, 'Rep. Bot. Congress,' London, 1866, p. 136, tab. 7, f. 15, 16.

This term is here made use of in the same sense as in descriptive botany, to indicate the isolation of parts of the same whorl; it is thus the opposite of cohesion. Morren, as has been previously stated, employed the word in a different sense, while Moquin-Tandon[75]included cases of this description under the category of "Disjonctions qui isolent les organes."

Dialysis, as here understood, may be the result of an arrest of development, in consequence of which parts that under ordinary circumstances would become fused, do not do so; or, on the other hand, it may be the result of an actual separation between parts primitively undivided. As it is not possible in every case to distinguish between the effects of these two diverse causes, no attempt is here made to do so.

Dialysis of the margins of individual foliar organs.—In cases where the leaf or leaf-like organ is ordinarily tubular or horn-like in form, owing to the cohesion of its edges, it may happen either from lack of union or from actual separation of the previously united edges, that the tubular shape is replaced by the ordinary flattened expansion. Thus, inEranthis hyemalis, wherein the petals (nectaries) are tubular and the sepals flat, I have met with numerous instances of transition from the one form to the other, as shown in fig. 9, p. 24.

It is, however, in the carpels that this separation occurs most frequently. When these organs appear under the guise of leaves, as they often do, their margins are disunited, so that the carpel becomes flat or open. This happens in the strawberry (Fragaria), the columbine (Aquilegia), inTrifolium repens,Ranunculus Ficaria, &c.[76]

Dialysis of the parts of the same whorl:—calyx.—The separation of an ordinarily coherent series into its constituent parts is necessarily of more common occurrence than the foregoing. As here understood, it is the precise converse of cohesion, and it may be represented diagrammatically by a dotted line above the letters denoting the sepals, petals, &c. When this change happens in the calyx we have the gamosepalous condition replaced by the polysepalous one, as thus represented:

.............S S S S Sinstead of_____________S S S S S

as in a calyx of five coherent sepals.

Detachment of this kind occurs not unfrequently, as inPrimula vulgaris,Trifolium repens, &c. InRosaceæandPomaceæthis separation of the calyx is of the more moment, as it has reference to the structure of theinferior ovary, as will be more fully mentioned hereafter. Here, however, a case recorded by M. J. E. Planchon may be alluded to[77]wherein a quince fruit (Cydonia) was surmounted by five leaves, the surface of the pome being marked by as many prominences, which apparently corresponded to the five stalks of the calycine leaves. In this specimen, then, the inferior position of the ovary appeared to be not so much due to an expansion of the fruit stalk, as to the fusion of the hypertrophied stalks of the sepals. Some of the malformations among Cucurbits point to a similar structure. It is probable that in many of these cases the so-called inferior ovary is partly axial partly foliar,i.e., sepaline, and partly carpellary in its nature.

Dialysis of the sepals in calyces that are usually gamosepalous has been most frequently observed inRosaceæ,Pomaceæ,Umbelliferæ, less commonly inLeguminosæ, also in the following genera:—Primula,Symphytum,Gentiana,Campanula, &c.

Fig.30.—Dialysis of the sepals and petals inCorrea.

Dialysis of the corollais likewise of frequent occurrence, either partially or to such an extent as to render the corolla truly polypetalous. AmongLabiatæthe upper lip of the corolla may be often met with partiallycleft, as it is constantly inPhlomis biloba, or more markedly among theLobeliaceæ.

In theCompositæ, a similar separation of the petals is not infrequent, thus showing frequent transitional stages between the labiatifloral and tubulifloral divisions respectively. The ligulate corollas also may often be found in Chrysanthemums, Dahlias, &c., more or less deeply divided into their component parts.

A more complete separation occurs not unfrequently inCampanula,Rhododendron,Phlox,&c.Figs. 30 and 31 illustrate dialysis of the corolla; the first inCorrea, the second inCampanula.

Fig.31.—Dialysis of the corolla inCampanula sp., after De Candolle.

In the last-named genus,C. rotundifoliahas been found with polypetalous flowers in a wild state in the mountains of Canton Neufchatel, Switzerland, and gave rise to the creation of a new genus. This form is now introduced into gardens.

It must be remembered that in some genera, where this separation of the petals has been met with, there are species in which a similar isolation occurs normally, as inRhododendron.R. linearilobum, a Japanese species, offers a good illustration of this.

The following list contains the names of the generain which this separation of the petals of an ordinarily gamopetalous flower takes place most frequently.

Correa.Campanula! sp. pl.Polemonium.Phlox!Cobœa!Rhododendron!Erica!Rhodora.Azalea!Compositæ! sp. pl.Lonicera!Convolvulus!Pharbitis.Antirrhinum!Verbascum!Mimulus.Digitalis!Orobanche.Solanum.Nicotiana.Gentiana!Anagallis.Primula!Lamium!Convallaria!Lilium!Colchicum!&c. &c.

This list does not include those very numerous cases in which this change is associated with more or less complete frondescence or leafy condition of the petals.

Dialysis of the stamens.—A similar isolation of the stamens occurs occasionally; for instance, when Mallows (Malvaceæ) become double, one of the first stages of the process is often the disjunction of the stamens, and a similar dissociation occurs inLeguminosæandCompositæ, as inTragopogon, as related by Kirschleger, inHypochærisby Wigand, and inCoreopsisby Schlechtendal.

Dialysis of the carpels.—In the case of the carpels this disunion is more frequent than in the stamens. M. Seringe[78]figures carpels ofDiplotaxis tenuifoliamore or less completely separated one from the other; indeed, this separation is very common amongstCruciferæandUmbelliferæ.

Generally speaking, the disunion is complicated with frondescence—but not always so. I have, in my herbarium, specimens ofConvallaria majalis,Commelyna sp., and ofLilium auratum, in all of which the three carpels are completely disjoined, and present threestyles, three stigmas, &c., without any other change. Engelmann[79]speaks of three classes of this malformation. 1st, that in which the carpels separate one from the other without opening, as in the lily just alluded to; 2nd, that in which the ovary remains closed, but loses its internal partitions, as in a case mentioned by Moquin inStachys sylvatica, in which, owing to imperfect disjunction, the two bi-lobed carpels were changed into a nearly one-celled capsule;[80]and 3rd, those cases in which the carpels are open and foliaceous.

Fig.32.—Anomalous form of orange.

Disjunction is more frequent in dry fruits than in fleshy ones. In the latter instance it happens at an early stage of existence, and the pericarp becomes more or less leafy, losing its faculty of becoming fleshy, as inPrunus CerasusandAmygdalus persica; nevertheless, fleshy fruits sometimes become disunited. I have seen a case similar to that mentioned by M. Alphonse de Candolle inSolanum esculentum, in which the pericarp became ruptured, and the placentas protruded. A like occurrence has also been observed in a species ofMelastoma.[81]This is analogous to what happens inCaulophyllumandSlateria. Disjunction of the carpelsis not rare in oranges. Sometimes this takes place regularly, at other times irregularly; occasionally in such a manner as to give the appearance of a hand and fingers to the fruit. Of one of these, Ferrari,[82]in the curious volume below cited, speaks thus: "Arbor profusissima, quia dat utraque manu; imo quia vere manus dat in poma conversis; utque magis munifica sit poma ipsa convertit in manus."

M. Duchartre[83]mentions a semi-double flower of orange with eight to ten distinct carpels in a whorl, and occasionally several whorls one above another. De Candolle[84]considers the rind of the orange as a production from the receptacle, and this view is confirmed by the specimens of Duchartre, in which the carpels were quite naked or had a common envelope truncated, and open above to allow of the passage of the styles and stigmas.

Fig.33.—Orange. Showing disjunction of carpels, after Maout.

Fig.34.—Section of orange shown in fig. 33 after Maout.

It frequently happens in conjunction with this separation of the carpels one from the other, that a lack of union manifests itself between the margins of the individual carpels themselves. Very numerous cases of this kind have been recorded, and the double tulips of gardens may be referred to as showing this conditionvery frequently. In connection with this detachment of the carpels, a change in the mode of placentation is often to be observed, or two or more kinds may be seen in the same pistil, as in double-flowered saponarias, many Crucifers, &c., as alluded to under the head of displacements of the placenta.

FOOTNOTES:[75]Loc. cit., p. 298.[76]Masters in Seemann's 'Journal of Botany,' 1867, p. 158.[77]Bull. Soc. Bot. France,' t. xiii, 1866, p. 234.[78]'Bull. Bot.,' pl. i, figs. 8–12.[79]'De Anthol.,' p. 37.[80]Moquin, loc. cit., p. 305.[81]'Neue Denkschr. der Allg. Schweiz. Gesell.,' band v, pl. ii. p. 5.[82]'Hesperides,' auctore Ferrario. Rome, 1646, fig. 415, pp. 213 and 215. See also Michel, 'Traité du Citronnier.'[83]'Ann. des Science Nat.,' 3rd series, 1844, vol. i, p. 294.[84]'Org. Véget.,' vol. ii., p. 41.

[75]Loc. cit., p. 298.

[76]Masters in Seemann's 'Journal of Botany,' 1867, p. 158.

[77]Bull. Soc. Bot. France,' t. xiii, 1866, p. 234.

[78]'Bull. Bot.,' pl. i, figs. 8–12.

[79]'De Anthol.,' p. 37.

[80]Moquin, loc. cit., p. 305.

[81]'Neue Denkschr. der Allg. Schweiz. Gesell.,' band v, pl. ii. p. 5.

[82]'Hesperides,' auctore Ferrario. Rome, 1646, fig. 415, pp. 213 and 215. See also Michel, 'Traité du Citronnier.'

[83]'Ann. des Science Nat.,' 3rd series, 1844, vol. i, p. 294.

[84]'Org. Véget.,' vol. ii., p. 41.

The isolation or separation of different whorls that are ordinarily adherent together is by no means of rare occurrence. Were it not that the isolation is often congenital, the word detachment would be an expressive one to apply to these cases, but as the change in question occurs quite as often from a want of union, an arrest or stasis of development, as from abonâ fideseparation, the word solution seems to be, on the whole, the best. It corresponds in application to the wordliber(calyx liber, &c.), in general use by descriptive botanists. As here employed, the term nearly corresponds with the "adesmie hetérologue" of Morren. Moquin Tandon does not make any special subdivision for the class of cases here grouped together, but places them all under "Disjonctions qui isolent les organes." It seems, however, desirable to have a separate word to express the converse condition of adhesion, and for this purpose the term solution, as above stated, is here employed. Diagrammatically, the condition may be expressed by placing a dotted line at the side of the letters thus:

: S S S S S :: C C C C C :

would indicate the disjunction of the sepals from thecarpels (c), in contradistinction to adhesion, which may be represented by the unbroken line thus:

| S S S S S || C C C C C |

Solution of the calyx from the ovary.—Of all the instances of adhesion which take place under ordinary circumstances, that between the calyx and the ovary is perhaps the most common. Thecalyx adhærensorsuperusis a structural characteristic to which all botanists attach considerable importance; so that when exceptional cases occur in which the calyx becomes detached from the ovary, becomes, that is,inferusorliber, a proportionate degree of interest attaches to the irregularity. It is not within the scope of the present work to inquire whether this detachment be real or merely apparent, arising from a want of union between parts ordinarily united together. This point must be left to the organogenists to decide in each particular case. So also the question as to what share, if any, the expanded and dilated flower-stalk may take in what are usually called inferior ovaries, can be here only incidentally touched upon.

AmongRosaceæ, the change in question is very common, especially in conjunction with an elongation of the axis of the flower (apostasis) and with prolification, though it is by no means always co-existent with these malformations. When this alteration in the apparent relative position of calyx and carpels occurs in roses (Rosa) the appearances are generally such as to indicate that the "hip" of the rose is a dilatation of the peduncle, continuous above with the coherent bases of the sepals; this inference seems also to be borne out by what happens in thePomaceæ. In some cases in this sub-order, the calyx becomes detached from the carpels, so that the latter organs become more or less "superior," and distinct one from the other. This happens constantly in the double-floweredthorn,Cratægus Oxyacantha, in some blossoms of which the hollowed end of the peduncle still invests the base of the carpels, leaving the upper portions detached. In apples flowers are occasionally met with of greater size than usual and on longer stalks, so that the whole looks more like a rose than an apple blossom. In these cases it will usually be found that the calyx consists of distinct sepals, without a trace of the ordinary swelling beneath the flower. The petals are often more numerous than usual; the stamens variously changed, and the carpels sometimes absent; at other times, as in the instance figured in the adjacent woodcuts, figs. 36, 37, consisting of separate, superior ovaries, sometimes destitute of ovules, or, at other times, having two of these bodies.[85]

Fig.35.—Proliferous Rose. Showing an absence of the usual dilatation of the flower-stalk, and other changes.

This condition accords precisely with the accountof the development of the flowers inPomaceæas given by Payer, Caspary, and others, so that the flowers above described would owe their deficiency of the swollen receptacle to an arrest of development. M. Germain de Saint Pierre, among other malformations of the rose, presented to the Botanical Society of France in 1854[86]two specimens which are of special interest as relating to this contested point. In the one, the swollen portion beneath the flower was surmounted by five perfect leaves, as, indeed, is not infrequent in such malformations; here, then, the calyx could have had little or no share in the production of the swelling in question. In the other, the swollen portion was actually above the insertion of the sepals here represented by five perfect leaves.

Fig.36.—Section through Apple blossom, showing detachment of calyx from ovaries, absence of dilated flower-stalk, &c.

Fig.37.—Calyx detached from carpels in Apple.

On the other hand, M. Planchon's specimen of the Quince before alluded to, not to mention other instances, tends to show that the bases of the sepals do sometimes enter into the composition of the pome. And, indeed, in many of these cases it would be impossible to say where the axial or receptacular portion ended, and the foliar portion began. As both fromnormal organogeny as well as from unusual conformation contradictory inferences may be drawn, it would obviously be unsafe to attempt the explanation of the so-called calyx-tube in general from any particular instances; so far asRosaceæare concerned, there is so much variation in the relative position of calyx and carpels under ordinary circumstances, that it is no matter for surprise that similar diversities should exist in teratological cases. A similar remark will apply toSaxifragaceæ,Cucurbitaceæ,Myrtaceæ,Bruniaceæ,Rubiaceæ, and other families of like conformation.

Fig.38.—Flower ofŒnanthe crocata, in which the five sepals were completely detached from the ovaries, here three in number and destitute of stylopods.

InUmbelliferæ, a detachment of the calyx from the ovaries frequently occurs, sometimes without any other change; at other times attended by more serious alterations. So far as can be judged from exceptional occurrences of this kind, it would appear that in this order the axis or flower-stalk does not, in any material degree, enter into the composition of the fruit.

In the Rubiaceous genusBikkhia, as mentioned by Duchartre, the ovary is completely inferior, but when the fruit arrives at maturity four small leaves are detached from its surface which had previously adhered to it, and which it seems reasonable to consider as the sepals.

InCampanulaceæa similar separation of calyx from the ovary may be occasionally met with. On the other hand, the occasional formation of a leaf on the inferior ovary of those plants would indicate the axial nature of the fruit. InCampanumæaandCyclodonthe calyx is inferior, while the corolla is superior. In the last-named genus this peculiarity "is carried to the highest degree, the sepals being, inC. parviflorum, placed on the peduncle of the flower far removed from the base of the corolla and ovary, whilst inC. truncatumand inCampanumæathey adhere to the base of the tube of the corolla."[87]In this order, then, as inSaxifragaceæ,Bruniaceæ, &c., no hasty conclusion should be drawn as to the nature of the fruit. InBrunia microphyllathe ovary is superior, enclosed within but not adnate to the cup-like calyx, to which latter, however, the petals and stamens are attached.

InOnagraceæ(Jussieua), as also inCactaceæ(Opuntia), buds have been observed on the surface and edges of the inferior ovary. Indeed, in the former genus, they have been produced artificially, but as buds may be formed on foliar as well as on axial organs, the fact cannot be made great use of in support either of the foliar or axial nature of the inferior ovary. InEpilobium, I have met with four perfect leaves at the summit of the ovary, in the place usually occupied by the sepals. This would also favour the notion that the axis entered into the constitution of the fruit in this genus.

Mr. B. Clarke, in his 'New Arrangement of Phanerogamous Plants,' p. 4, cites a case wherein the perianth was completely detached from the surface of the ovary inCannabis sativa.

It must be borne in mind that some of the recorded instances of change in the relative position of the calyx and pistil ought more properly to be referred to a substitution of carpels for stamens, as inBegonia,Fuchsia, &c. AmongCucurbitaceæ, examples have been recorded, both of the detachment of the calyx from the ovary,[88]and of the partial conversion of some of the anthers of the male flower to carpels.

The very singular mode of germination ofSechium edulein which the fruit, instead of rotting, becomes thickened into a kind of rhizome or tuber, is a fact that should not be overlooked in investigating the true nature of the fruit in this order.

The following are the genera in which the change has been most frequently observed:

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