FOOTNOTES:

Fig.105.—Fig showing prolonged inflorescence and projecting flowers.

Fig.106.—Section of the same.

Altered direction of leaves.—The leaves partake more or less of the altered direction of the axis, as in fastigiate elms, but this is not universally the case, for though the stem is bent downwards the leaves may be placed in the opposite direction; thus in some specimens ofGalium Aparinegrowing on the side of a cliff from which there had been a fall of chalk, the stems, owing apparently to the landslip, were pendent, but the leaves were abruptly bent upwards.

One of the most singular instances of an inverteddirection of the leaves is that presented by a turnip (fig. 107) presented to the Museum of King's College, London, by the late Professor Edward Forbes. The turnip is hollow in the interior and the majority of the leaves springing from its apex instead of ascending into the light and air become bent downwards so as to occupy the cavity, and in such a manner as to bring to mind the position of an inverted embryo in a seed.

Fig.107.—Hollow turnip, showing some of the leaves inverted and occupying the cavity.

Altered direction of the flower and its parts.—The changes which take place in the relative position either of the flower as a whole or of its several parts during growth are well known, as also are the relations which some of these movements bear to the process of fertilisation, so that but little space need here be given to the subject beyond what is necessary to point out the frequent changes of direction which necessarily accompanyvarious deviations from the ordinary form and arrangement of parts.

In cases where an habitually irregular flower becomes regular, the change in form is frequently associated with an alteration in direction both of the flower as a whole and, to a greater or less extent, of its individual members, for instance ofGloxinia, the normal flowers of which are irregular and pendent, there is now in common cultivation a peloriate race in which the flowers are regular in form and erect in position.

Fig.108.—Flower of normalGloxinia.

Fig.109.—Flower ofGloxinia, erect and regular (regularPeloria).

Fig. 108 shows the usual irregular form ofGloxinia, with which may be contrasted figs. 109, 110 and 111.

Fig. 109 shows the regular erect form; fig. 110 the calyx of the same flower; while in fig. 111 are shown the stamens and style of the two plants respectively. In the upper figure the style of the peloriate variety is shown as nearly straight, and the stamens undergo a corresponding change. No doubt the relative fertility and capacity for impregnation of the two varieties is affected in proportion to the change of form. The Gloxinia affords an instance of regular congenital peloria in which the regularity of form and the erect direction are due to an arrest, not of growth, but of development, in consequence of which the changes that ordinarily ensue during the progress of the flower from its juvenile to its fully formed condition do not take place.

Fig.110.—Calyx of erectGloxinia.

Fig.111.—Stamens of erect regular, and of pendent irregular-floweredGloxinia.

A similar alteration accompanies this form of peloria in other flowers (see Peloria). A change in direction may result also from other circumstances than those just alluded to. Abortion or suppression of organs will induce such an alteration; thus in a flower ofPelargoniumnow before me three of the five carpels, from some cause or other, are abortive and much smaller than usual, and the style and the beak-liketorus are bent downwards towards the stunted carpels instead of being, as they usually are, straight.

Amongst orchids, where the pedicel of the flower or the ovary is normally twisted, so that the labellum occupies the anterior or inferior part of the flower, it frequently happens, in cases of peloria and other changes, that the primitive position is retained, the twist does not take place, and so with other resupinate flowers. In Azaleas a curious deflexion of the parts of the flower may occasionally be met with. Fig. 112 shows an instance of this in which the corolla, the stamens and the style were abruptly bent downwards: as young flowers of this singular variety have not been examined it is difficult to form an opinion as to the cause of this variation. In one plant the change occurred in connection with the suppression of all the flowers but one in the cluster, or rather the place of the flowers was occupied by an equal number of leafy shoots.

Fig.112.—Flower ofAzalea, showing the corolla reflected.

Moquin[213]mentions a flower ofRosa alpinain which two of the petals were erect, while the remaining ones were much larger and expanded horizontally. The same author quotes from M. Desmoulins the case of a species ofOrobanche, in which a disjunction of the petals constituting the upper lip took place, thus liberatingthe style and allowing it to assume a vertical direction.

Fig.113.—Flower ofCuphea miniataenlarged, showing protrusion and hypertrophy of an erect placenta, after Morren.

Fig.114.—Placenta from the flower shown at fig. 113; the ovary is membranous and torn, the placenta, erect and ovuliferous, after Morren.

M. Carrière[214]has described an instance wherein two apples were joined together, a larger and a smaller one; the former was directed away from the centre of the tree as usual, while the smaller one was pointed in exactly the opposite direction. The larger fruit had thecustomary parchment-like carpels, the smaller was destitute of them.

Sometimes the direction assumed by one flower as an abnormal occurrence is the same as that which is proper to an allied species or genus under natural circumstances; thus flowers of the vine (Vitis) have been met with in which the petals were spreading like a star (fleurs avalidouires), as in the genusCissus.[215]

Morren describes a curious condition in some flowers ofCuphea miniata, in which the placenta protruded through an orifice in the ovary, and losing the horizontal direction became erect (figs. 113, 114). A similar occurrence happened inLobelia erinus. To this condition the Belgian savant gave the name of gymnaxony.[216]

FOOTNOTES:[210]The following details as to the method pursued by Mr. McNab, of the Edinburgh Botanic Garden, may not be uninteresting in this place. They are from the pen of Mr. Anderson, and originally appeared in the 'Gardeners' Chronicle.'"The mode of inducing leaders to proceed from laterals is a matter of comparatively little concern among the generality of deciduous trees, for they are often provided with subsidiary branches around the leader, at an angle of elevation scarcely less perpendicular, but the laterals of all Conifers stand, as nearly as possible, at right angles. Imagine the consternation of most people when the leader of, say,Picea nobilis,P. Nordmanniana, orP. Lowiiis destroyed."In a specimen of the latter plant the leader had been mischievously destroyed, to remedy which Mr. McNab adopted means which Mr. Anderson goes on to describe. "Looking from the leader downward to the first tier of laterals, there appeared to have been a number of adventitious leaf-buds created, owing to the coronal bud being destroyed. These were allowed to plump up unmolested until the return of spring, when every one was scarified or rubbed off but the one nearest the extremity. To assist its development and restrain the action of the numerous laterals, every one was cut back in autumn, and this restraint upon the sap acted so favorably upon the incipient leader as to give it the strength and stamina of the original leader, so that nothing detrimental was evident twelve months after the accident had happened, and only a practical eye could detect that there had been any mishap at all. This beautifully simple process saved the baby tree."Another example of retrieving lost leaders may be quoted as illustrative of many in similar circumstances.Pícea Webbianahad its leader completely destroyed down to the first tier of laterals. There was no such provision left for inducing leaf-buds as was the case withP. Lowiiabove referred to. Resort must, therefore, be had to one of the best favoured laterals, but how is it to be coaxed from the horizontal position of a lateral to the perpendicular position of a leader? The uninitiated in these matters, and, in fact, practical gardeners generally, would at once reply, by supporting to a stake with the all-powerful Cuba or bast-matting. But no. A far simpler method than that, namely, by fore-shortening all the laterals of the upper tier but the one selected for a leader. Nature becomes the handmaid of art here; for without the slightest prop the lateral gradually raises itself erect, and takes the place of the lost leader. All that the operator requires to attend to is the amputation of the laterals until this adventitious fellow has gained a supremacy. Singular provision in nature this, which, thanks to the undivided attention of a careful observer, has been fully appreciated and utilized."[211]'Variation of Animals and Plants,' ii, p. 277.[212]Quoted in 'Gard. Chron.,' 1867, p. 654.[213]Loc. cit., p. 315.[214]'Rev. Hortic.,' 1868, p. 110.[215]Planchon and Marès, 'Ann. Sc. Nat.,' 5 ser., tom. vi, 1866, p. 228, tab. xii.[216]'Bull. Acad. Belg.,' xviii, part ii, p. 293.

[210]The following details as to the method pursued by Mr. McNab, of the Edinburgh Botanic Garden, may not be uninteresting in this place. They are from the pen of Mr. Anderson, and originally appeared in the 'Gardeners' Chronicle.'"The mode of inducing leaders to proceed from laterals is a matter of comparatively little concern among the generality of deciduous trees, for they are often provided with subsidiary branches around the leader, at an angle of elevation scarcely less perpendicular, but the laterals of all Conifers stand, as nearly as possible, at right angles. Imagine the consternation of most people when the leader of, say,Picea nobilis,P. Nordmanniana, orP. Lowiiis destroyed."In a specimen of the latter plant the leader had been mischievously destroyed, to remedy which Mr. McNab adopted means which Mr. Anderson goes on to describe. "Looking from the leader downward to the first tier of laterals, there appeared to have been a number of adventitious leaf-buds created, owing to the coronal bud being destroyed. These were allowed to plump up unmolested until the return of spring, when every one was scarified or rubbed off but the one nearest the extremity. To assist its development and restrain the action of the numerous laterals, every one was cut back in autumn, and this restraint upon the sap acted so favorably upon the incipient leader as to give it the strength and stamina of the original leader, so that nothing detrimental was evident twelve months after the accident had happened, and only a practical eye could detect that there had been any mishap at all. This beautifully simple process saved the baby tree."Another example of retrieving lost leaders may be quoted as illustrative of many in similar circumstances.Pícea Webbianahad its leader completely destroyed down to the first tier of laterals. There was no such provision left for inducing leaf-buds as was the case withP. Lowiiabove referred to. Resort must, therefore, be had to one of the best favoured laterals, but how is it to be coaxed from the horizontal position of a lateral to the perpendicular position of a leader? The uninitiated in these matters, and, in fact, practical gardeners generally, would at once reply, by supporting to a stake with the all-powerful Cuba or bast-matting. But no. A far simpler method than that, namely, by fore-shortening all the laterals of the upper tier but the one selected for a leader. Nature becomes the handmaid of art here; for without the slightest prop the lateral gradually raises itself erect, and takes the place of the lost leader. All that the operator requires to attend to is the amputation of the laterals until this adventitious fellow has gained a supremacy. Singular provision in nature this, which, thanks to the undivided attention of a careful observer, has been fully appreciated and utilized."

"The mode of inducing leaders to proceed from laterals is a matter of comparatively little concern among the generality of deciduous trees, for they are often provided with subsidiary branches around the leader, at an angle of elevation scarcely less perpendicular, but the laterals of all Conifers stand, as nearly as possible, at right angles. Imagine the consternation of most people when the leader of, say,Picea nobilis,P. Nordmanniana, orP. Lowiiis destroyed."

In a specimen of the latter plant the leader had been mischievously destroyed, to remedy which Mr. McNab adopted means which Mr. Anderson goes on to describe. "Looking from the leader downward to the first tier of laterals, there appeared to have been a number of adventitious leaf-buds created, owing to the coronal bud being destroyed. These were allowed to plump up unmolested until the return of spring, when every one was scarified or rubbed off but the one nearest the extremity. To assist its development and restrain the action of the numerous laterals, every one was cut back in autumn, and this restraint upon the sap acted so favorably upon the incipient leader as to give it the strength and stamina of the original leader, so that nothing detrimental was evident twelve months after the accident had happened, and only a practical eye could detect that there had been any mishap at all. This beautifully simple process saved the baby tree.

"Another example of retrieving lost leaders may be quoted as illustrative of many in similar circumstances.Pícea Webbianahad its leader completely destroyed down to the first tier of laterals. There was no such provision left for inducing leaf-buds as was the case withP. Lowiiabove referred to. Resort must, therefore, be had to one of the best favoured laterals, but how is it to be coaxed from the horizontal position of a lateral to the perpendicular position of a leader? The uninitiated in these matters, and, in fact, practical gardeners generally, would at once reply, by supporting to a stake with the all-powerful Cuba or bast-matting. But no. A far simpler method than that, namely, by fore-shortening all the laterals of the upper tier but the one selected for a leader. Nature becomes the handmaid of art here; for without the slightest prop the lateral gradually raises itself erect, and takes the place of the lost leader. All that the operator requires to attend to is the amputation of the laterals until this adventitious fellow has gained a supremacy. Singular provision in nature this, which, thanks to the undivided attention of a careful observer, has been fully appreciated and utilized."

[211]'Variation of Animals and Plants,' ii, p. 277.

[212]Quoted in 'Gard. Chron.,' 1867, p. 654.

[213]Loc. cit., p. 315.

[214]'Rev. Hortic.,' 1868, p. 110.

[215]Planchon and Marès, 'Ann. Sc. Nat.,' 5 ser., tom. vi, 1866, p. 228, tab. xii.

[216]'Bull. Acad. Belg.,' xviii, part ii, p. 293.

In a morphological point of view the form of the various parts or organs of plants and the changes to which they are subjected during their development are only second in importance to the diversities of arrangement and, indeed, in some cases, do not in any degree hold a second place.

Taken together, the arrangement, form, and number of the several parts of the flower, make up what has been termed the symmetry of the flower.[217]Referring to the assumed standard of comparison,see p. 4, it will be seen that in the typically regular flower all the various organs are supposed to be regular in their dimensions and form. At one time it was even supposed that all flowers, no matter how irregular theysubsequently became, began by being strictly symmetrical or regular, and that subsequent alterations were produced by inequality of growth or development. The researches of organogenists have, however, dispelled this idea of unvarying primordial regularity, by showing that in many cases flowers are irregular from the very first, that some begin by being irregular, and subsequently become regular, and even in some cases resume their original condition during the course of their development.[218]Under these circumstances an artificial standard of comparison becomes almost an absolute necessity for the time being.

Changes of form very generally, but not always, are accompanied with a change in regularity: thus a flower habitually bi-lateral may assume the characters of radiating symmetry andvice versâ. Increase or decrease of size very frequently also are co-existent with an alteration in the usual form.

In the case of the arrangement of organs it is often difficult or impossible, in the present state of our knowledge, to determine whether a given arrangement is congenital or acquired subsequently to the first development, whether for instance an isolation of parts be due to primordial separation or to a subsequent disunion of originally combined organs,see p. 58. With reference to the changes in the form of organs, however, it is in general more easy to ascertain the proximate cause of the appearance, and thus teratological changes of form may be grouped according as they are due to, 1, arrest of development; 2, undue or excessive development; 3, perverted development; and 4, irregular development; hence the use of the followingterms—Stasimorphy, Pleiomorphy, Metamorphy, and Heteromorphy—to include teratological changes really or apparently due to one or other of the causes above mentioned. The classification here adopted is of course to a considerable extent an arbitrary one and subject to correction or modification, as the knowledge of the development of the flowers in the various genera of plants advances.

FOOTNOTES:[217]The word symmetry has been used in very different senses by different botanists, sometimes as synonymous with "regularity," at other times to express the assumed typical form of a flower. Payer understands it to be that arrangement of parts which permits of the whole flower being divided vertically into two symmetrical halves (bi-lateral symmetry). Others, again, have applied the term symmetry to the number of the parts of the flower, reserving the terms "regularity" or "irregularity" for the form. It is here used in a general sense to express the plan of the flower, and thus includes the arrangement, form, and number of its component elements.[218]See Baillon, 'Adansonia,' v, 176.

[217]The word symmetry has been used in very different senses by different botanists, sometimes as synonymous with "regularity," at other times to express the assumed typical form of a flower. Payer understands it to be that arrangement of parts which permits of the whole flower being divided vertically into two symmetrical halves (bi-lateral symmetry). Others, again, have applied the term symmetry to the number of the parts of the flower, reserving the terms "regularity" or "irregularity" for the form. It is here used in a general sense to express the plan of the flower, and thus includes the arrangement, form, and number of its component elements.

[218]See Baillon, 'Adansonia,' v, 176.

Deviations from the ordinary form of organs arising from stasis or arrest of development are included under this heading.

There are many cases in which the forms proper to a juvenile condition of the plant are retained for a much longer period than ordinary, or even throughout the life of the individual growth goes on, but "development" is checked. Such conditions may even be propagated by seed or bud. It is a very general thing for botanists to consider these cases as reversions to a simpler, primitive type, and this may be so; but on the other hand, they may be degenerations from a complex type, or they may have no direct relation to any antecedent condition. Stasimorphic changes affecting principally the relative size of organs—such, for instance, as the non-development of internodes, or the atrophy or suppression of parts will be found mentioned in the sections relating to those subjects. In the present part those alterations which affect the form of organs principally are treated of.

FOOTNOTES:[219]Στασις-μορφωσις.

[219]Στασις-μορφωσις.

The retention in adult life of a form characteristic of an early stage of development, and therefore usually transient, may be manifested in any of the organs of the plant. As these cases are for the most part treated under separate headings, it is here only necessary to allude to a few, which it is difficult to allocate satisfactorily, while the reader may be referred for other instances of like nature to the sections on Peloria, Atrophy, Suppression, Dimorphy, Substitutions, &c.

Fig.115.—Juniperus sinensis. Two forms of leaves on branches of the same shrub.

Stasimorphy in the leaves of conifers.—In many conifers the leaves produced in the young state of the plant are different, both in arrangement and form, from those subsequently developed (see pp. 89, 90). But itoccasionally happens that the plant continues to form throughout its existence leaves such as are usually produced only in a young state; thus M. Gubler ('Bull. Soc. Bot., Fr.,' vol. viii, 1861, p. 527) describes a plant ofPinus pineain which the primordial, usually transitory, foliage was permanent, leaves of the ordinary shape not being developed at all. It more often happens that some only of the leaves retain their young form while others assume other shapes, see fig. 115. This happens frequently in the larch and constantly in the Chinese juniper when it has arrived at a considerable age. InCupressus funebristwo forms of leaves may often be found on the same plant, the one representing the juvenile state, the other the more developed condition. What is very singular, is that a cutting taken from the branch with leaves of the young form grows up into a shrub bearing leaves of no other shape, so that an ordinary observer unacquainted with the history of the plant would imagine that he had to deal with two distinct species. This fact is the more interesting when compared with the alternation of generations which takes place among the lower animals.

The regular development of all the parts of the flower in a plant habitually producing irregular flowers is referred to under the head of Peloria, but it still remains to consider those examples in which some only of the parts of the flower are affected in this manner.[220]Most of these cases are elsewhere referred to in this volume under the particular form of malformation assumed; but the following case may here be noticed as not coming under any of the previous heads. It is an instance recorded by Professor Babington ('Phytologist,' August, 1853), and in which the pod ofMedicago maculata, which is usually rolled up like a snail shell and provided with spines, was sickle-shaped and unarmed.

FOOTNOTES:[220]See a paper of Professor C. Morren's on "Floral Stesomy" in 'Bull. Acad. Belg.,' t. xix, part ii, p. 519.

[220]See a paper of Professor C. Morren's on "Floral Stesomy" in 'Bull. Acad. Belg.,' t. xix, part ii, p. 519.

Fig.116.—Regular Peloria,Delphinium.

Fig.117.—Sepal, petal, &c., of regular-floweredDelphinium.

Fig.118—Regular peloria,Viola.

Fig.119—Double Violet, flower regular, petals multiplied, stamens and pistils petaloid.

When an habitually irregular flower becomes regular, it does so in one of two ways; either by the non-development of the irregular portions, or by the formation of irregular parts in increased number, so that the symmetry of the flower is rendered perfect, as in the original peloria of Linnæus, and which may be called irregular peloria, while the former case may be called regular peloria. This latter appearance is therefore congenital, and due to an arrest of development.[221]As the true nature of these cases has not been in all cases recognised (even Moquin places them under the head of deformities—they being less entitled to rank in that class than are the usual flowers), it may be well to cite a few instances taken from various families. InDelphinium peregrinumI have met with perfectly regular flowers having five sepals and five oblong stalked petals, and a similar occurrence has been notedin other species of this genus. Baillon,[222]in referring to these flowers, points out the resemblance that they bear to the double varieties ofNigella. In the stellate columbines (Aquilegia) of gardens the tubular petals are replaced by flat ones often in increased numbers. In violets both forms of peloria occur, that in which there is an unusual number of spurs, and that in which there are no spurs (var. anectaria). In the more perfect forms of regular peloria occurring in the last-named genus the following changes may be noticed: 1, an alteration in the direction of the flower so that it remains in an erect position, and is not bent downwards as usual; 2, equality of proportion in the sepals and petals; 3, absence of spurs, as also ofhairs on the lateral petals; 4, equal stamens whose anthers are sometimes entirely destitute of the prolonged crest which forms so prominent a feature under ordinary circumstances; 5, erect, not curved styles, and the stigmas not prolonged into a beak, but having a more or less capitate form; ovary with three or five cells, ovules normal.

These are cases where the change in question is most strongly marked, the bi-lateral is completely replaced by the radiating symmetry. The absence of the usual nectary, and of hairs on the side petals, the alterations in the form of the style, etc., all show how much the process of fertilisation must be altered from that which occurs under ordinary circumstances. In some of the double violets now cultivated in gardens, a similar regularity of proportion in the parts of the flower may be seen combined with the substitution of petals for stamens and pistils, and with the development of an increased number of petal-like organs.[223]Between these cases and the ordinary spurred forms as well as those with an increased number of spurs, many intermediate forms may be met with. That such regularity should occur in this family is not to be wondered at seeing that there is a whole subdivision of the order (Alsodeiæ) in which regular flowers are the rule.

In cultivated Pelargoniums the central flower of the umbel or "truss" frequently retains its regularity of proportion, so as closely to approximate to the normal condition in the allied genusGeranium; this resemblance is rendered greater by the fact that, under such circumstances, the patches of darker colour characteristic of the ordinary flower are completely wanting; the flower is as uniform in colour as in shape. Even the nectary which is adherent to the upper surface of the pedicel in the normal flower disappears—sometimes completely, at other tunes partially. The direction of the stamens and style, and even that of the whole flower, becomesaltered from the inclined to the vertical position. In addition to these changes, which are those most commonly met with, the number of the parts of the flower is sometimes augmented, and a tendency to pass from the verticillate to the spiral arrangement manifested. Schlechtendal mentions some flowers ofTropæolum majusin which the flowers were perfectly regular and devoid of spurs[224], while in the double varieties, now commonly grown in greenhouses, the condition of parts is precisely the same as in the double violet before alluded to. Among thePapilionaceæthe Laburnum and others have been noticed to produce occasionally a perfectly regular flower in the centre, or at the extremity of the inflorescence, though the peloria in this flower is usually irregular. In the Gentianaceous genusHalenia,H. heteranthais remarkable for the absence of spurs. AmongstGesneraceæ,Bignoniaceæ,Scrophulariaceæ, and other families of like structure, regular peloria is not uncommon. Fig. 120 represents a case of this kind inEccremocarpus scaber, conjoined, as is frequently the case, with dialysis or separation of the petals.[225]Many of the cultivated Gloxinias also showerect, regular, five stamened flowers, but these are probably cases of irregular peloria.

Fig.120.—Regular peloria,Eccremocarpus scaber.

A solitary flower ofPedicularis sylvaticawas found by the Marquis of Stafford near Dunrobin Castle in Sutherlandshire, in which the usual ringent form of the corolla was replaced by the form called salver-shaped. There were six stamens, four long and two short. Sir W. Hooker and Mr. Borrer are stated to have found a similar flower in the same locality in 1809.[226]

The passage of ligulate to tubular corollas amongCompositæis not of such common occurrence as is the converse change. I owe to Mr. Berkeley the communication of a capitulum of a species ofBidens, in which there was a transition from the form of ligulate corollas to those that were deeply divided into three, four, or five oblong lobes. These then were instances of regular peloria.

Fig.121.—Flower ofCattleya marginata. Lip replaced by a flat petal.

InOrchidaceæa similar change is not by any means infrequent; in a few, indeed, a regular flower is the normalcharacter, as inDendrobium normale,Oncidium heteranthum,Thelymitra, etc. Fig. 121, reduced from a cut in the 'Gardeners' Chronicle,' 1854, p. 804, represents an instance of this kind inCattleya marginata.

From the same journal the following account of a case of peloria inPhalænopsis Schillerianais also cited as a good illustration of this peculiar change. The terminal flower differed entirely from all the others; instead of the peculiar labellum there were three petals all exactly alike, and three sepals also exactly alike; the petals resembled those of the other flowers of the spike, and the upper sepal also; but the two lower sepals had no spots, and were not reflexed as in the ordinary way: thus, these six parts of the flower were all in one plane, and being close together at their edges, made almost a full round flower; the column and pollen-glands were unaffected. Professor Reichenbach also exhibited at the Amsterdam Botanical Congress, of 1865, a flower ofSelenipedium caudatumwith a flat lip.

M. Gris[227]has placed on record some interesting cases of peloria of this kind inZingiber zerumbet; in the more complete forms the andrœcium or staminal series was composed of six distinct pieces, the three inner of which were fertile, while in the ordinary flower the andrœcium is composed of two pieces, "a lip" and a fertile stamen. "Is it not a matter of regret," says M. Gris, "to be obliged to call the latter the normal flower?"

Under this head may likewise be mentioned those cases in which the normal, or at least the typical symmetry of the flower is restored by the formation of parts usually suppressed; thus Moquin cites an abnormal flower ofAtriplex[228]hortensisdescribed by M. Fenzl as having a true calyx within the two bracts that usually alone encircle the stamens. Adanson, also cited by Moquin, found a specimen ofBocconiawith acorolla.Arum maculatumhas likewise been met with provided with a genuine perianth as inAcorusand other Orontiads. The unusual development of the sexual organs in diclinous flowers has been alluded to under the head of heterogamy, and other cases where the symmetry of the flower is rendered regular, by the development of parts ordinarily suppressed, will be found in the chapters relating to deviations from the usual number of organs.

This change, or rather this persistence of a form that is usually transient, is generally accompanied by some other alterations. Change of direction, as has been already mentioned, is one of the most common of these; separation of the petals (Antirrhinum,Verbascum, &c.), and even their appearance in leaf-like guise, are not infrequent (Delphinium,Antirrhinum,Verbascum, &c.) At other times multiplication or increased number of the whorls of petals takes place, often, but not always, at the expense of the sexual organs of the flower. Perhaps even more frequent is the increased number of parts in the same whorl in cases of regular peloria; thus, in the Pelargoniums before alluded to, the parts of the flower are frequently regulated by the number six instead of five.

This form of peloria is most generally met with in flowers that are placed at the end or in the centre of the inflorescence, or in such flowers as occur singly at the end of the flower-stalk, as inTropæolum,Viola, &c. It would hence seem as if the freedom from pressure or restriction on one side allowed the flower to develop equally in all directions, and thus to produce regularity of form.

It is obvious, from what has been before said, that the process of fertilisation is in many cases interfered with and altered by the change in the conformation or the flower.

From overlooking the occasional existence of this form of peloria, new genera have sometimes been formed on insufficient grounds. The genusAceranthus,for instance, consists of species ofEpimediumin which the customary spurs are not formed.[229]

The occurrence both of regular and irregular peloria on the same plant has frequently been observed inLinaria. It has also been remarked that the seedlings raised from these forms are not always constant; thus, the late Mr. Crocker, formerly foreman in the Royal Gardens, Kew, informed me that he fertilised some flowers of a drooping Gloxinia with their own pollen, and that when the seedlings blossomed a large number of them produced the erect regular flowers.

From what has been already said it will be seen that regular peloria is closely allied to what Morren called epanody, or a return to the normal condition. The reversion of a monstrous form to the normal one, as, for instance, when the fern-leaved beech reverts to the normal type, was called by the same author epistrophy.[230]

The following are the genera in which regular peloria has been most often observed. It must, however, be remarked that in some of the flowers recorded as peloric there is no indication as to which form of peloria the case should be referred to. For other illustrations refer to chapters on Heterogamy, Number, Irregular Peloria, &c.

*Delphinium peregrinum!*Nigella damascena!*Aquilegia vulgaris!*Viola odorata!hirta.Epimedium, sp.*Pelargonium zonale!*inquinans!Tropæolum majus!*Wistaria sinensis.Lupinus.*Cytisus Laburnum!Trifolium repens!*Compositæ, gen. pl.!Lonicera Periclymenum!Streptocarpus Rexii.*Digitalis purpurea.*Scrophularia aquatica.*Pentstemon.*Linaria vulgaris!*Antirrhinum majus!Verbascum nigrum!Columnea Schiedeana.Halenia heterantha.Galeobdolon luteum.Prunella vulgaris!Salvia, sp.!Teucrium campanulatum.Betonica alopecuros.Eccremocarpus scaber.Pedicularis sylvatica.Zingiber Zerumbet.Phalænopsis amabilis!Phalænopsis Schilleriana.Habenaria.*Orchis morio.mascula.*Dendrobium, sp.Atriplex, sp.Cattleya Mossiæ!marginata.Calanthe vestita!Oncidium, sp.!Selenipedium caudatum.Arum maculatum.

In addition to the references already given, further information on this subject may be gained from consulting the following publications. See also Irregular Peloria.

Giraud, 'Bot. Soc. Edinb.,' Dec. 12, 1839,Antirrhinum. Dareste, 'Ann. Sc. Nat.,' ser. 2, 1842, xviii, p. 220,Delphinium. C. Morren, 'Fuchsia,' p. 90,Calceolaria, 'Bull. Acad. Belg.,' xx, part ii, p. 57; and E. Morren, 'Bull. Acad. Belg.,' 2nd ser., xix. p. 224,Gloxinia. Richard, 'Mém. Soc. d'hist. nat.,' ii, p. 212, tab. 3. Lindley, 'Journ. Linn. Soc.,' iii, p. 9,Dendrobium. Michalet, 'Bull. Soc, Bot. France,' vii, p. 625,Betonica. Gubler, 'Bull. Soc. Bot. Fr.,' ix, 81, 'Des anomalies aberrantes et regularisantes.' Reichenbach fil. 'De pollinis orchid. genesi ac structura,' 1852,Oncidium. Clos, 'Mém. Acad. Toulouse,' vi, 1862,Salvia. Caspary, 'Verhandl. Phys. Œkon. Gesell. Königsberg,' 1860, i, 59,Columnea. Bureau, 'Bull. Soc. Bot. Fr.,' 1861, vol. viii, p. 710,Streptocarpus. Darwin, 'Variation of Animals and Plants,' ii, pp. 59 and 396. Godron, 'Ex. Bull. Bot. Soc. Fr.,' xiv, p. 165, 'Rev. Bibl.,'Wistaria. Marchand, 'Adansonia,' iv, p. 172,Lonicera. Baillon, 'Adansonia,' v, p. 177, 'Sur la regularité transitoire de quelques fleurs irreg.,' shows that during the development of some flowers which begin and end by being irregular, there is an intermediate state when all the parts are regular. Helye, 'Revue Horticole,' Sept., 1868, p. 327. In this last paper, published as this sheet is going through the press, the author states that he has raised from seed three generations of plants ofAntirrhinumwith regular spur-less flowers. The original wild plant was only partially peloric, but all the flowers produced on its descendants were regular.

FOOTNOTES:[221]"On the existence of two forms of Peloria," by M. T. Masters. 'Nat. Hist. Review,' April, 1863.[222]Baillon, 'Adansonia,' iv. p. 149.[223]Similar cases are figured in 'Hort. Eystettens. Ic. Pl. Vern.' fol. 4, f. 1, 2.Viola martiamultiplici flore.[224]'Linnæa,' 1837, p. 128.[225]M. Bureau, 'Bull. Soc. Bot. Fr.,' ix, p. 91, describes two genera ofBignoniaceæin which the flowers arenormallyregular and six parted.[226]See 'Trans. Linn. Soc.,' vol. x. p. 227.[227]'Ann. Sc. Nat.,' ser. 4, 1859. tom. xi, p. 264, tab. 3.[228]'El. Ter. Veg.,' p. 342.[229]Marchand, 'Adansonia,' vol. iv, p. 127.[230]'Bull. Acad. Belg.,' xvii. p. 17. "Fuchsia," p. 169.

[221]"On the existence of two forms of Peloria," by M. T. Masters. 'Nat. Hist. Review,' April, 1863.

[222]Baillon, 'Adansonia,' iv. p. 149.

[223]Similar cases are figured in 'Hort. Eystettens. Ic. Pl. Vern.' fol. 4, f. 1, 2.Viola martiamultiplici flore.

[224]'Linnæa,' 1837, p. 128.

[225]M. Bureau, 'Bull. Soc. Bot. Fr.,' ix, p. 91, describes two genera ofBignoniaceæin which the flowers arenormallyregular and six parted.

[226]See 'Trans. Linn. Soc.,' vol. x. p. 227.

[227]'Ann. Sc. Nat.,' ser. 4, 1859. tom. xi, p. 264, tab. 3.

[228]'El. Ter. Veg.,' p. 342.

[229]Marchand, 'Adansonia,' vol. iv, p. 127.

[230]'Bull. Acad. Belg.,' xvii. p. 17. "Fuchsia," p. 169.

Most irregular flowers owe their irregularity to an unequal development of some of their organs as compared with that of others. When such flowers become exceptionally regular they do so either because development does not keep pace with growth, and a regular flower is thus the result of an arrest of the former process (regular peloria), or because the comparatively excessive development, which usually occurs in a few parts is, in exceptional cases manifested by all, hence the flower becomes regular from the increase in number of its irregular elements. These latter cases, then, are due to an excess of development, hence the application of the term pleiomorphy. It must be understood that mere increase in the number of the organs of a flower is not included under this head, but under that of deviations from the ordinary number of parts.

FOOTNOTES:[231]Ρλειος-μορφωσις.

[231]Ρλειος-μορφωσις.

The term peloria was originally given by Linné to a malformation ofLinaria vulgaris, with five spurs and five stamens, which was first found in 1742 near Upsal. This was considered so marvellous a circumstance that the term peloria, from the Greekπελωρ, aprodigy, was applied to it.[232]After a time other irregular flowers were found in like condition, and so the term peloria became applied to all cases wherein, on a plant habitually producing irregular flowers, regular ones were formed. The fact that this regularity might arise from two totally different causes was overlooked, or at least not fully recognised, even by Moquin-Tandon himself. Where a flower retains throughout life the same relative size in its parts that it had when those parts first originated the result is, of course, a regular flower, as happens in violets and other plants. This kind of peloria may for distinction sake be called regular or congenital peloria (see chapter on that subject); but where a flower becomes regular by the increase in number of its irregular portions, as in theLinariaalready alluded to, where not only one petal is spurred, but all five of them are furnished with such appendages, and which are the result of an irregular development of those organs, the peloria is evidently not congenital, but occurs at a more or less advanced stage of development. To this latter form of peloria it is proposed to give the distinctive epithet of irregular.

Peloria is either complete or incomplete; it is complete when the flower appears perfectly symmetrical, it is incomplete when only a portion of the flower is thus rendered regular. It is very common, for instance, to find violets or Linarias with two or three spurs, and these intermediate stages are very interesting, as theyserve to show in what way the irregularity is brought about. InAntirrhinum,Linaria, &c., intermediate forms show very clearly that it is to the repetition of the form usually assumed by the petals of the lower lip that the condition is due. This is also obvious in peloric flowers of theCalceolaria. The perfect peloria of this flower is in general erect, with five regular sepals, a regular corolla contracted at the base and at the apex, but distended in the centre so as to resemble a lady's sleeve, tight at the shoulder and wrist, and puffed in the centre!

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