In speaking of these as cases of intra-carpellary prolification, it is, of course, impossible to overlook the fact that they differ in degree only from those cases where the lengthened axis projects beyond the cavity of the carpels; nevertheless they seem to demand special notice, because in these particular plants the placenta or its prolongation appears never to protrude beyond the carpels, or at least very rarely.

There are, however, numerous instances of such an extension of the placenta and of prolification occurring among _Primulaceae_ in conjunction with the more or less complete arrest of growth of the carpels.[130] An instance of this kind has come under my own notice in a monstrosity of the chinese primrose, in which the carpels were reduced to a hardly discernible rim surrounding an umbel of five rays, each terminated by a small normally const.i.tuted flower-bud.

The ovules of a prolified flower are either unaffected, or they occur in a rudimentary form, or, lastly, they may be present in the guise of small leaves.

Under the term prolification of the fruit two or three distinct kinds of malformation appear to have been included. The term seems usually to be applied to those cases where from the centre of one fruit a branch bearing leaves, flowers, or another fruit, is seen to project, as happens occasionally in pears. Now, in many instances, not only the fruit, is repeated, but also the outer portions of the flower, which wither and fall away as the advent.i.tious fruit ripens; so that at length the phenomenon of one fruit projecting from another is produced. It is obvious that this form of prolification in no wise differs from ordinary central prolification. Sometimes some of the whorls of the advent.i.tious flower are suppressed; thus, M. Duchartre describes some orange blossoms as presenting alternating series of stamens and pistils one above another, while the calyces and corollas belonging to each series of stamens and pistils were entirely suppressed.[131] In other cases, doubtless, the carpellary whorl is alone repeated, the other whorls of the advent.i.tious flower being completely absent.

Another condition, apparently sometimes mistaken for prolification of the fruit, is that in which the carpellary whorl becomes multiplied; so that there is a second or even a third series within the outer whorl of carpels. If the axis be at all prolonged, then these whorls are separated one from the other, and produce in this way an appearance of prolification. This happens frequently in oranges, as in the variety called Mellarose.[132]

Moquin has given an explanation of the St. Valery Apples, wherein the petals are sepaloid, the stamens absent, and where there is a double row of carpels, by supposing these peculiarities to be due to "a prolification combined with penetration and fusion of two or more flowers," but it is surely more reasonable to conceive a second row of carpels placed above the first by the prolongation of the central part of the axis. Supposing this view to be correct, the inner calyx-like whorl might be considered either as a repet.i.tion of the calycine whorl, or it might be inferred that the corolla was present in the guise of a second calyx.

Moquin-Tandon suggests another explanation--namely, that though the stamens are absent in these curious flowers, at least in their ordinary shape, they are represented by the lower row of carpels, which become, in process of development, fused with the upper or true carpels. If this were so, surely some intermediate conditions between stamen and carpel would occasionally be present; but such does not appear to be the case.[133]

In some of the instances of so-called proliferous pears the carpels would seem to be entirely absent, and the dilated portion of the axis to be alone repeated. Thus, the axis dilates to form the lower fruit without any true carpels being produced, but at its summit a whorl of leaves (sepals) is formed; above these another swelling of the axis takes place also without the formation of carpels, and this, it may be, is terminated in its turn by a branch producing leaves. In these cases there is no true prolification, but simply an extension of the axis.

That the outer portion (so-called calyx-tube) of these fruits is really an axile product there can now be little doubt; and, as if to show their axile nature, they occasionally produce leaves from their sides, as before mentioned. Moquin, in the tenth volume of the 'Bulletin of the Botanical Society of France,' p. 73, says that when the case is one of prolification the lower fruit is larger and is formed of a fleshy ma.s.s; moreover, the line of demarcation between the fruits is more distinct, and there are traces of the seed-bearing cavity in the interior, and of calycine lobes at the top. On the other hand, if the case be one of hypertrophy merely, the lowermost fruit is the smallest, and there is no trace of seed-bearing cavity nor of sepals. See also under Hypertrophy.

Some other malformations usually referred to prolification of the fruit seem due to branching of the inflorescence, as in _Plantago_, wheat, maize; or to a simple extension of the axis beyond its ordinary limit, as in some cones of firs, &c. It is obvious that the true fruits in these cases are in no wise affected.

From these considerations it would appear better to abandon the use of the expression prolification of the fruit, as unnecessary where it is really applicable, and as delusive in the numerous other cases where it is employed.

Median prolification of one or other kind has been met with in the following genera:

_Leafy_. _Floral_.

Ranunculaceae. Clematis.

Anemone! *Anemone!

Ranunculus! *Ranunculus!

Delphinium.

Caltha.

Aquilegia!

Cruciferae. Bunias.

*Cheiranthus!

Erucago.

*Matthiola!

Sisymbrium!

Bra.s.sica!

Nasturtium.

Hesperis.

Sinapis!

Diplotaxis.

Lunaria.

Erysimum.

Alyssum.

Peltaria.

Cardamine!

Cleome.

Cistaceae. Helianthemum!

Caryophylleae. Dianthus! *Dianthus!

Silene!

Lychnis!

Violaceae. Viola!

Tiliaceae. Triumfetta!

Geraniaceae. Geranium!

Sapindaceae. Pavia! Pavia!

Malvaceae. Paritium.

Hibiscus!

Malpighiaceae. Byrsonima!

Rutaceae. Genera not specified. *Dictamnus!

Resedaceae. Reseda.

Caylussa!

Aurantiaceae. *Citrus!

Vitaceae. Vitis. Vitis.

Umbelliferae. Heracleum.

Angelica.

Thysselinum.

*Athamanta.

*Daucus!

*Torilis.

Rosaceae. *Rosa! *Rosa!

*Geum! *Geum!

Agrimonia. Amygdalus.

Prunus!

Spiraea! Spiraea!

Rubus.

*Pyrus! *Pyrus!

?Leguminosae Trifolium!

Medicago!

Melilotus.

Pisum!

Cucurbitaceae. Cuc.u.mis.

Pa.s.sifloraceae. Pa.s.siflora.

Philadelphaceae. Philadelphus.

Onagraceae. Epilobium!

Epacridaceae. Epacris!

Ericaceae. *Erica.

Rhododendron!

Convolvulaceae. Convolvulus.

Gentianaceae. Gentiana. Gentiana.

Apocynaceae. Vinca.

Jasminaceae. Jasminum!

Scrophulariaceae. Verbasc.u.m! Antirrhinum!

*Digitalis!

*Linaria!

Veronica.

Orobanchaceae. Orobanche.

l.a.b.i.atae. Genera not specified. Stachys.

Phlomis!

Hydrophyllaceae. Hydrophyllum.

Boraginaceae. Anchusa.

Symphytum.