Vegetable Teratology. Maxwell T. Masters
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 in Pinus 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.
CHAPTER II.
DIALYSIS.
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, in Eranthis 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), in Trifolium 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 S
instead of
_____________
S S S S S
as in a calyx of five coherent sepals.
Detachment of this kind occurs not unfrequently, as in Primula vulgaris, Trifolium repens, &c. In Rosaceæ and Pomaceæ this separation of the calyx is of the more moment, as it has reference to the structure of the inferior 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 in Rosaceæ, Pomaceæ, Umbelliferæ, less commonly in Leguminosæ, also in the following genera:—Primula, Symphytum, Gentiana, Campanula, &c.
Fig. 30.—Dialysis of the sepals and petals in Correa.
Dialysis of the corolla is likewise of frequent occurrence, either partially or to such an extent as to render the corolla truly polypetalous. Among Labiatæ the upper lip of the corolla may be often met with partially cleft, as it is constantly in Phlomis biloba, or more markedly among the Lobeliaceæ.
In the Compositæ, 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 in Campanula, Rhododendron, Phlox, &c. Figs. 30 and 31 illustrate dialysis of the corolla; the first in Correa, the second in Campanula.
Fig. 31.—Dialysis of the corolla in Campanula sp., after De Candolle.
In the last-named genus, C. rotundifolia has 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 in Rhododendron. R. linearilobum, a Japanese species, offers a good illustration of this.
The following list contains the names of the genera in which this separation of the petals of an ordinarily gamopetalous flower takes place most frequently.
Correa.