Vegetable Teratology Part 53

In the 'Revue Horticole,' 1867, p. 71, fig. 9, is described and figured by M. B. Verlot a curious variety of vine grown for years in the Botanic Garden at Gren.o.ble, under the name of the double-flowered vine. The place of the flower is occupied by a large number of successive whorls of sepals disposed in regular order, and without any trace of the other portions of the flower. It is, in fact, more like a leaf-bud than a flower. The outermost whorls of this flower open at the time when the ordinary flowers of vines do; the second series are gradually produced, and expand about the time when the ovaries of the normal flowers begin to swell; a third series then gradually forms, and so on, until frost puts a stop to the growth. This malformation, it appears, is produced annually in certain varieties of vine, and may be perpetuated by cuttings.

The flower of the St. Valery apple, already alluded to under the head of sepalody, might equally well be placed here. It is not very material whether the second whorl of organs be regarded as a repet.i.tion of the calyx or as a row of petals in the guise of sepals.

Engelmann[432] cites the following plants as occasionally presenting a repet.i.tion of the calyx, in most cases with a suppression of the other floral whorls:--_Stachys lanata_, _Myosotis pal.u.s.tris_, _Veronica media_, _Aquilegia vulgaris_, _Nigella damascena_, _Campanula rapunculoides_.

=Pleiotaxy in the perianth.=--Increase in the number of whorls in the perianth is common in lilies, narcissus, hyacinths, &c. It may be also met with occasionally among orchids. The lily of the valley (_Convallaria maialis_) seems also to be particularly subject to an increase in the number of parts of which its perianth consists, the augmentation being due partly to repet.i.tion or pleiotaxy, partly to the subst.i.tution of petaloid segments for stamens and pistils.[433]

In this place may also be mentioned the curious deviation from the ordinary structure occasionally met with in _Lilium candidum_, and known in English gardens as the double white lily. In this case there are no true flowers, but a large number of petal-like segments disposed in an irregular spiral manner at the extremity of the stem, some of the uppermost being occasionally verticillate.[434]

[Ill.u.s.tration: FIG. 190.--Double white lily. Multiplication of perianth-segments and other changes.]

=Pleiotaxy of the corolla.=--With reference to double flowers, it was remarked by Linne that polypetalous flowers were, as he said, multiplied, while monopetalous flowers were duplicated, or triplicated, as the case may be,[435] a statement that is true in the main, though it requires modification. In the case of polypetalous, or rather dialypetalous flowers, the petals may be very largely increased by multiplication, as in roses, anemones, pinks, &c. In the last-named genus the number is often so much increased that the calyx splits from the tension exercised on it by the increasing ma.s.s within. This multiplication may happen without any metamorphy or subst.i.tution of petals for stamens, though, in the majority of cases, it is a.s.sociated with such a change. It is curious to observe in some of these flowers that the total number of parts is not greatly increased; thus, in some of the double-flowered _Leguminosae_, such as _Ulex europaeus_ and _Lotus corniculatus_, the petals are repeated once or twice, the stamens are petalodic, but reduced in number, while the carpels are usually entirely wanting. Thus, owing to the diminished number of parts in the inner whorls of the flower, these very double-looking blooms do not contain any greatly increased number of parts.[436]

Flowers that, under ordinary circ.u.mstances, are gamopetalous, become, in some instances, multiplied by the formation of additional segments, just as in the case of polypetalous corollas; but in these cases the corollas become polypetalous, their petals do not cohere one with another. Among double flowers of this character may be mentioned _Campanula rotundifolia_, _Gardenia_ sp., _Nerium Oleander_, _Serissa_ sp., _Arbutus Unedo_, &c. The change is a.s.sociated with petalody of the stamens and pistils.

A more frequent change among the monopetalous orders is the duplication or triplication of the corolla, in consequence of which there appear to be a series of corollas enclosed one within the other, the lobes of which generally alternate with one another, but which sometimes are superposed. This happens occasionally in the primrose (_Primula acaulis_), and const.i.tutes the variety called by the gardeners "hose in hose."

The same condition occurs frequently in some species of _Datura_ and _Campanula_.

[Ill.u.s.tration: FIG. 191.--_Campanula rotundifolia_. "Double flowers"

resulting from dialysis and multiplication of the petals.]

In _Antirrhinum majus_ double flowers of this character sometimes occur; the outermost corolla is normal, the succeeding ones usually have their petals separate one from the other; the stamens are sometimes present, sometimes absent, and at other times petalodic. Similar occurrences may be met with in l.a.b.i.ates and jasmines, and in _Erica hyemalis_.

Mr. W. B. Hemsley has kindly furnished me with flowers of a similar kind occurring in wild specimens of _Epacris impressa_,[437] and there are a.n.a.logous phenomena in the common honeysuckle (_Lonicera Periclymenum_), in which three corollas and no stamens often occur.

This duplication may either be accounted for on the theory of chorisis above alluded to, or by supposing that the extra corolline whorl is due to a series of confluent petalodic stamens; that the latter is the true explanation, in certain cases at least, is shown by some flowers of _Datura fastuosa_, in which the second corolla was partially staminal in its appearance, and bore nearly perfect anthers, in addition to the five ordinary stamens, which were unaltered either in form or position. Some partially virescent honeysuckle flowers have a similar structure.

There are other cases of apparent multiplication or duplication, due, probably, rather to the formation of outgrowths from the petals than to actual augmentation of their number. These excrescences occur sometimes on the inner surface of the petals, or of the corolla; at other times on the outer surface, as in some gloxinias, &c. This matter will be more fully treated of under the head of hypertrophy and enation.

=Pleiotaxy of the androecium.=--An increase in the number of whorls in the stamens is very common, especially in cases where the number of circles of stamens is naturally large. The augmentation of the number of stamens is still more frequent where these organs are arranged, not in verticils, but in one continuous spiral line.

In _Cruciferae_ there is always an indication of two whorls of stamens, and this indication is rendered even more apparent in some varieties accidentally met with. So in _Saponaria_, in _Dianthus_, and other _Caryophylleae_, three and four verticils of stamens have been met with.

In _Lonicera Periclymenum_ a second whorl of stamens more or less petalodic sometimes occurs.

Moquin mentions a variety of _Rubus fruticosus_ in which nearly 900 petaloid organs existed in the place of the twenty-five or thirty stamens natural to the plant, the other organs of the flower being in their ordinary condition, with the exception of the pistil, which did not attain its full size. Baillon records the occasional existence of two rows of stamens in _Ditaxis lancifolia_.

=Increased number of stamens in orchids, &c.=--Various deviations from the ordinary type of orchid structure have been already alluded to under the head of displacement, fusion, peloria, subst.i.tution, &c., but the alterations presented by the androecium in this family are so important in reference to what is considered its natural conformation, that it seems desirable, in this place, to enter upon the teratological appearances presented by the androecium in this order, in somewhat greater detail than usual. The ordinary structure of the flower with its three sepals, two petals, labellum, column; and inferior ovary, is well known. Such a conformation would be wholly anomalous and inexplicable were it not that the real number and arrangement of parts have been revealed by various workers labouring to the same end in different fields. Thus, Robert Brown, Link, Bauer, Darwin, and others, paid special attention to the minute anatomy and mode of distribution of the vessels; Irmisch, Crueger, Payer, and others, to the evolution of the flower; Lindley, St. Hilaire, and Reichenbach, to the comparison of the completed structures in the various genera and species; while the teratological observers have been numerous, as will be seen from the selected references cited at the end of this paragraph and in other places. The result of this manifold study has been a pretty general agreement that the structure of the order (omitting minor details) is as follows:--A six-parted perianth in two rows, the outer three (sepals) generally regular and equal in shape; of the inner three (petals or tepals) two are regular, and one, the labellum very irregular, consisting not only of a petal, but of two abortive stamens incorporated with it. The column is considered to be made up of one perfect and three abortive stamens, in inseparable connection with three styles. By some, however, it is supposed that all the stamens are confluent with the column and none with the lip.

[Ill.u.s.tration: FIG. 192.--Diagram showing the arrangement of parts in an orchid flower. According to Cruger, the stamens A 2, A 3, should be distinct from the lip. The uppermost figure 2 should have been 1. (See text.)]

In either case it is admitted that there are six stamens in two rows.

The first row consists of one posterior stamen, which is generally perfect, and two abortive stamens incorporated with the labellum. The second row also consists of three stamens, all of which are usually abortive and inseparable from the column. Traces of them may occasionally be met with in the form of tubercles or wing-like processes from the column. In _Cypripedium_, while the ordinary stamen of the outer row is deficient, two of the inner series are present. The diagram, fig. 192, will serve to show the arrangement of the parts as above described. + represents the situation of the stem or axis; on the opposite side is the bract; between these are placed the sepals, one posterior or next the axis (incorrectly numbered 2 in the plan), two lateral 1, 1; next in order follow the petals, 2, 2, 2, two lateral and somewhat posterior, one larger (the lip), anterior; the outer series of stamens are represented by A 1, A 2, A 3, the two latter being fused with the labellum; _a_ 1, _a_ 2, _a_ 3 represent the position of the inner verticil of stamens, while s, s, s denote the three carpels. It is foreign to the purpose of this book to detail the varied evidence in support of this explanation of the h.o.m.ologies of orchid flowers.[438]

All that can be done in these pages is to set forth the evidence furnished by teratology as to this matter--evidence for the most part acc.u.mulated and recorded without any special reference to any theory of orchid structure.

The following details all refer to flowers in which the number of stamens in orchidaceous plants was increased beyond what is necessary.

They are arranged with reference to the number of advent.i.tious organs, beginning with those in which the number was smallest, and proceeding thence to those in which it was greatest. In some cases it has not been possible to ascertain whether the advent.i.tious organs were really restorations of the numerical symmetry, subst.i.tutions of one part for another, stamen for petal, &c., or wholly advent.i.tious productions.

Unless otherwise stated, the interpretation put upon the facts thus recorded is that of the present writer, and not necessarily that of the original observer.

Mr. J. T. Moggridge has described and figured a flower of _Ophrys insectifera_ in which there was a vestige of a second stamen present, probably one of the inner series fig. 192 (_a_^2).[439] The same observer also records the presence of a second anther between the lobes of the normal one. This can hardly be referred to either of the typical stamens, but would seem to be a perverted development of the rostellum.[440]

Roeper is stated by Cramer[441] to have seen a specimen of _Orchis morio_ with two stamens.

In a flower of _Habenaria chlorantha_, described by the late Professor Henslow,[442] the outer three stamens are suppressed, while two of the inner group are present, as happens normally in _Cypripedium_.

A flower of _Cattleya violacea_ afforded a similar ill.u.s.tration; but in this case only one of the inner stamens was developed, and this in the form of a small petal, partly adherent to the column.

In _Dendrobium normale_, Falconer, not only is the perianth regular, but the column is triandrous,[443] the three stamens (according to the diagram of its structure given by Lindley) pertaining to the outer row.

In a specimen of _Dendrobium hoemoglossum_ kindly forwarded from Ceylon by Mr. Thwaites there were three stamens present, of which one posterior belonged to the outer series A 1, and two lateral to the inner _a_ 1, _a_ 2, fig. 192.

M. His observed, several years in succession, some flowers of a species of _Ophrys_ with three sepals, no lateral petals, one lip, and three perfect stamens. In this case probably the two supernumerary stamens were petals which had a.s.sumed an anther-like character.

Wydler describes a flower of _Ophrys aranifera_ in which one outer and two inner stamens were present.[444] I have myself met with three such flowers in the same species. The stamens present were A 1, _a_ 1, _a_ 2.

Dr. J. E. Gray exhibited at the Botanical Society of London, in August, 1843, a specimen of _Ophrys apifera_ with a triandrous column, the supernumerary anthers belonging, apparently, to the inner whorl.

In his 'Catalogue of the Plants of South Kent,' p. 56, tab. iv, f. 16, the Rev. G. E. Smith describes and figures a flower of _O. aranifera_ with a triandrous column, seemingly of the same kind as that spoken of by Dr. Gray.

Mr. Moggridge met with a triandrous flower in the same species, and refers the appearance to "a fusion of two flowers, accompanied by suppression and modification."[445] As, however, no details are given in support of this opinion, it may be conjectured that the two additional stamens were members of the inner whorl _a_ 1, _a_ 2, and thus the conformation would be the same as in the flowers just mentioned. The figures given by Mr. Moggridge bear out this latter view, while they lend no support to the hypothesis advanced by him. Nevertheless, no decided opinion can be p.r.o.nounced by those who have not had the opportunity of examining the flowers in question.

Alphonse de Candolle[446] figures a flower of _Maxillaria_ in exactly the same condition, so far as the stamens are concerned, as in the Ophrys flowers just mentioned. It is curious to observe that in many of these cases the two lateral petals are suppressed.

Von Martius mentions the occurrence of three anthers (_naturaliter conformatae_) in _Orchis morio_.[447] Richard, as cited by Moquin-Tandon, Lindley, and others, describes and figures a peloria of _Orchis latifolia_ with regular triandrous flowers.[448]

The writer has examined, in the Royal Gardens at Kew, a flower of _Cattleya crispa_ in which were three stamens, the central one normal; the two lateral ones, belonging probably to the inner whorl, were in appearance like the lateral petals, and one of them was adherent to the central perfect column.

Duchartre[449] mentions a flower of _Cattleya Forbesii_ in which there were two labella in addition to the ordinary one, the column being in its normal condition. From the a.n.a.logy of other cases it would appear as if the additional labella in this instance were the representatives of two stamens of the outer whorl. Beer likewise has put on record the existence of a triandrous _Cattleya_.[450]

A specimen of _Catasetum eburneum_ forwarded by Mr. Wilson Saunders was normal so far as the sepals and two lateral petals were concerned, but the anterior petal or labellum was flat and in form quite like the two lateral ones; the column was normal and in the situation of the two anterior stamens of the outer series A 2, A 3, were two labella of the usual form (fig. 156, p. 291). Perhaps the _Oncidium_ represented at p. 68, fig. 29, may also be explained on the supposition that the two lateral lobes of the labellum in this flower were the representatives of stamens.

In Fig. 193 is shown the arrangement of parts in a flower of _Ophrys aranifera_. Here there were three sepals, two lateral petals, one of which was adherent to the side of the column; the central labellum was seemingly deficient, but there were two pseudo-labella placed laterally in the position of the two antero-lateral stamens of the outer series (A 2, A 3). Within these was another perfect stamen occupying the position of the anterior stamen of the inner series (_a_ 3). In another flower of the same species, gathered at the same time (fig. 194), there were three sepals not at all different from those of the normal flower. The three petals next in succession were also, in form and position, in their ordinary state. In colour, however, the two upper lateral petals differed from what is customary, in having the same purplish-brown tint which characterises the lip. Within these petals, at the upper part of the flower, there was the ordinary column, and at the opposite side, alternating with the petals before mentioned, two additional lip-like petals, one provided with a half-anther containing a single perfectly formed pollen-ma.s.s (A 2, A 3). It is, perhaps, worthy of notice that the arrangement of the coloured spots on the true labellum, and that on the advent.i.tious lips, replacing the two lower of the outer stamens, were not of a similar character. The supernumerary lips had the [Greek: pi]-shaped marking which is so common in this species, while the true lip was, as to its spots, much more like _O. apifera_. Alternating with this last whorl were three columns, all apparently perfectly formed and differing only from the ordinary one in their smaller size and corresponding to _a_ 1, _a_ 2, _a_ 3. The ovary in this flower was two-celled, with four parietal placentas, thus giving an appearance as though there had been a fusion of two or more flowers a.s.sociated with suppression and other changes. The position of the supernumerary organs and the absence of any positive sign of fusion in the bracts or other part of the flower, seemed, however, to negative the idea of fusion.[451]

[Ill.u.s.tration: FIG. 193.--Diagram showing the arrangement of parts in a malformed flower of _Ophrys aranifera_ (see p.

384).]

[Ill.u.s.tration: FIG. 194.--Malformed flower of _Ophrys aranifera_ with two supernumerary lips and three additional stamens.]

A similar ill.u.s.tration, for a knowledge of which the writer is indebted to the kindness of Professor Asa Gray and Mr. Darwin, occurred in some specimens of _Pogonia ophioglossoides_ collected by Dr. J. H. Paine in a bog near Utica, New York. It will be seen from the following description that these flowers presented an almost precisely similar condition to those of the _Ophrys aranifera_ just mentioned. "The peculiarities of these flowers," writes Professor Gray, "are that they have three labella, and that the column is resolved into small petaloid organs. The blossom is normal as to the proper perianth, except that the labellum is unusually papillose, bearded almost to the base. The points of interest are, first, that the two accessory labella are just in the position of the two suppressed stamens of the outer series, viz. of A2 and A3, as represented in the diagram, fig. 192; and there is a small petaloid body on the other side of the flower, answering to the other stamen, A1.

Secondly, in one of the blossoms, and less distinctly in another, two lateral stamens of the inner series (_a_1 and _a_2) are represented each by a slender naked filament. There are remaining petaloid bodies enough to answer for the third stamen of the inner series and for the stigmas, but their order is not well to be made out in the dried specimens." It may here be mentioned that _Isochilus_ is normally triandrous.

A tetrandrous flower of _Cypripedium_ has also been recorded.

In _Isochilus_, according to Cruger, there are often five stamens, and there are several, besides those already mentioned, in which six more or less perfect stamens have been seen--of these the following may be taken as ill.u.s.trations. A hexandrous flower of _Orchis militaris_ has been recorded by Kirschleger,[452] and in the accompanying diagram (fig. 195), from Cramer,[453] of a monstrous flower of _Orchis mascula_, there is one perfect stamen of the outer row and two lip-like stamens of the same series, while the inner verticil comprises one perfect and two abortive stamens.

[Ill.u.s.tration: FIG. 195.--Diagram of flower of _Orchis mascula_ with two additional lips, two perfect and two imperfect stamens (after Cramer).]

Morren[454] describes some flowers of _Orchis morio_ in which there were three sepals, three petals, and within the latter two other ternary series of petals; this would seem to be a case of petalody of all six stamens. Morren, however, seems to have considered the additional segments as repet.i.tions of the corolline whorl, though he describes a central ma.s.s as the column bearing a "_souvenir_ of the anther." Nevertheless, there is no decisive evidence either in his figure or his description in support of his opinion as to the nature of the central ma.s.s, which might be a distorted condition of the styles, or, as is more probable, a rudimentary and irregular flower. Morren also describes another flower of the same plant in which there were three sepals, two lateral petals partially lip-like in aspect, a third labellum normal, two additional labella representing the two anterior stamens of the outer whorl, while more or less developed rudiments of the remaining four stamens also exist.