Vegetable Teratology. Maxwell T. Masters
Changes of this kind among Orchidaceæ are by no means uncommon; the following may be cited by way of illustration. In a specimen of Oncidium cucullatum furnished me by Mr. Anderson, well known for his success as a cultivator of these plants, there was, associated with a cohesion of one sepal with another, and probably dependent on the same cause, a displacement of the sepals and petals—so that all were dragged out of place. This dislocation may be better appreciated by the accompanying formula than even by the woodcut. Let the usual arrangement be thus represented:
S
P ST P
L
S S
S standing for sepal, P for petal, L for lip, ST for stamen; then the dislocated form may be represented thus:
S
P P
T
S
S_S
L
Fig. 43.—Flower of Oncidium cucullatum, showing union of two lower sepals, displacement of column and lip, &c.
In a specimen of Cypripedium also furnished by Mr. Anderson the appearance was as represented in the accompanying figure and diagrams, figs. 44, 45. Referring to the plan of the natural arrangement at fig. 46, it will be seen that an explanation of the peculiar appearance of the flower may be arrived at by supposing a disunion and lateral displacement of the upper segment of the outer perianth together with the complete absence of the lower one. In the second or inner whorl of the perianth the lip is merely a little oblique on one side, but the lateral petals are distorted, displaced, and adherent one to the other and to the column, while the posterior shield-like rudimentary anther is completely wanting.
Fig. 44.—Malformed flower of Cypripedium.
Fig. 45.—Diagram of malformed Cypripedium. o, outer segments; i, inner segments of perianth; e, lip; s, stigma; a, anther.
Fig. 46— Diagram showing ordinary arrangement in Cypripedium. o, outer, i, inner segments of perianth; e, lip, a, anther, a', abortive stamen; s, stigma.
Fig. 47.—Plan of flower of Lycaste Skinneri showing displacement of organs.
In a specimen of Lycaste Skinneri similar changes were observed, as shown in the plan, fig. 47. Here the posterior sepal was deficient, the two lateral ones were present, one of them with a long tubular spur, o o; of the two lateral petals, i i, one was twisted out of place, so as partially to occupy the place of the deficient sepal; the lip was represented by two three-lobed segments, l, one above and within the other. The column and ovary of this flower were in their normal condition.
Cohesion of two or more segments of the perianth is frequently associated with displacements of this nature: thus, in a flower of Dendrobium nobile, a diagram of which is given at fig. 48, the uppermost sepal was coherent with one of the lateral ones, and at the same time diminished in size, and, as it were, dragged out of position. All the other organs of the flower are also more or less displaced, forming a minor degree of the change already alluded to, and which Morren termed speiranthy. The changes will be better appreciated by comparing them with fig. 49, a diagram showing the natural arrangement of parts in this species.
Fig. 48.—Plan of malformed flower of Dendrobium nobile.
Fig. 49.—Plan of natural arrangement in Dendrobium nobile. The x x represent processes of the column, perhaps rudiments of stamens.
Sometimes the displacement seems consequent on hypertrophy of one of the parts of the flower, the disproportionate size of one organ pushing the others out of place. This was the case in a violet, fig. 50, in which one of the sepals s was greatly thickened, and the petals and stamens were displaced in consequence.
Fig. 50.—Plan of flower of violet showing displacement of petals, &c. At b was a rudiment of a stamen.
It is curious to observe in many of these cases that the transposed organ not only occupies the place of a suppressed or abortive organ, but frequently assumes its colour, and, to some extent, its function. This has been alluded to in the case of the leaf of Gesnera (see p. 88) and in Orchids this replacement seems to be very common; thus, in addition to the cases before mentioned, in a flower of an Odontoglossum, for which I am indebted to Professor Oliver, the two lateral sepals were united together and occupied the position of the labellum, which was absent. A similar occurrence happens occasionally in Lycaste Skinneri, thus recalling the structure of Masdevallia, where the labellum is normally very small. The arrangement in Lycaste may thus be symbolised:
S
P st P
+
S S
---
the + indicating the position of the absent labellum.
Cases of this kind are the more interesting from their relation to the fertilization of these flowers by insects; it seems as though, when the labellum, which performs so important an office in attracting and guiding insects, is deficient, its place is supplied by other means.
Displacement of the parts of the flower from elongation of the receptacle is a not infrequent teratological occurrence, resulting sometimes in the conversion of the verticillate into the spiral arrangement. Instances of this are cited under Elongation, Prolification, &c. In this place it is merely necessary to refer to a curious circumstance that is met with in some double flowers, owing to this separation of some parts of the flower and the cohesion or adhesion of others. Thus, in some double flowers of Primula sinensis and in the Pea (Pisum sativum), I have seen a gradual passage of sepals to petals, so that the calyx and corolla formed one continuous sheet, winding spirally around the central axis of the flower, after the fashion of a spiral tube.[98]
Displacement of the carpels arises from one or other of the causes above alluded to, and when suppression takes place in this whorl it generally happens that the place of the suppressed organ is occupied by one of the remaining ones, which thus becomes partially dislocated.
Displacement of the placentas and ovules is a necessary result of many of the changes to which the carpels are subject. The disjunction or dialysis of the carpels, for instance, frequently renders axile placentation marginal. Moreover, it frequently happens, when the carpels become foliaceous and their margins are disconnected, that the ovules, in place of being placed on the suture, or rather on the margins of the altered carpel, are placed on the surface of the expanded carpel. Thus, in some double flowers of Ranunculus Ficaria that came under the writer's notice the carpels were open, i.e. disunited at the margins, and each bore two imperfect