Allamanda!

Tabernaemontana.

*Calystegia!

Convolvulus!

Ipomoea.

*Datura!

*Petunia!

Solanum!

Orobanche.

Gentiana.

Mimulus.

*Antirrhinum!

Gratiola!

*Digitalis!

*Linaria!

Veronica!

Calceolaria!

Achimenes.

Gloxinia!

Clerodendron!

Bignonia.

Cyclamen!

Mirabilis.

Laurus!

Gladiolus!

Crocus!

Iris!

*Galanthus!

Leucojum!

Sternbergia!

Hippeastrum.

*Narcissus!

*Orchis!

Catasetum!

Hydrocharis.

Asphodelus.

*Tulipa!

Scilla.

*Convallaria!

Fritillaria!

*Lilium!

*Hyacinthus!

*Polianthes!

*Hemerocallis!

*Colchic.u.m!

*Sagittaria!

*Tradescantia!

Commelyna!

Tofieldia.

=Petalody of the pistils.=--Taken by itself, this is much less common than the corresponding change in the stamens. It generally affects the style and stigma only, as happens normally in _Petalostylis_, _Iris_, &c., but this is by no means always necessarily the case. In some of the cultivated varieties of _Anemone_ and _Ranunculus_ all the parts of the flower remain in their normal state, except the pistils, which latter a.s.sume a petaloid appearance.

Many of the double flowers owe their peculiar appearance to the combination of the following appearances--a petal-like form of the stamens, increase in the number of these organs and similar changes affecting the pistils, and is applied to several distinct conditions. If in any given flower all the stamens and all the pistils become wholly petaloid, no pollen is formed, and of course no seeds can be produced, but this very rarely happens, as usually some pollen is produced, and some ovules capable of being fertilised are developed.

In double flowers of _Primula sinensis_ it frequently happens that the capsule is either partially leafy or partly petal-like; in either case the fruit is open at the extremity, and often dest.i.tute of the style and stigma. It is, however, doubtful if the ovules can be fertilised in these flowers.

The following list comprises the names of those genera in which this change has been most frequently observed, independently of corresponding alterations in the stamens, but it is more usual for both sets of organs to be similarly affected.

*Ranunculus!

*Anemone!

Nigella.

*Papaver!

*Dianthus!

Saponaria!

Viola!

Camellia!

Alcea.

Hibiscus!

Amygdalus!

Lonicera!

Scabiosa.

aeschynanthus!

Primula!

=Petalody of the ovules.=--The princ.i.p.al changes which occur in the ovule have already been alluded to at pp. 262-272; it may here be stated, however, that the ovules are occasionally represented by small stalked petal-like structures. This happens with especial frequency among _Cruciferae_.[313]

=Petalody of the accessory organs.=--A petaloid condition of the disc, of the scales, or other excrescences from the axis or from the lateral portions of the flower, is of frequent occurrence, though it is but rarely that the change is of any great importance in a morphological point of view. C. Morren has given the name adenopetaly to a case wherein one of the glands at the base of the petals in _Lopezia_ was replaced by a petal.[314] A similar change may be seen in the double Oleander.

=Staminody of the bracts.=--An instance of this has been already alluded to in _Abies excelsa_, as observed by Prof. d.i.c.kson, and in which some of the bracts were seen a.s.suming the form and characteristic of the stamens see _ante_: p. 192. Signor Licopoli met with a similar subst.i.tution of anthers for bracts in _Melianthus major_.[315]

=Staminody of the sepals and petals.=--In the first named this is of very rare occurrence. M. Gris has recorded an instance in _Philadelphus speciosus_[316] which appears to be the only case on record. The corresponding change in the case of the petals is far more common. De Candolle cites in ill.u.s.tration of this occurrence flowers of the common haricot, in which the alae and carina of the corolla were thus changed.[317] There is in cultivation a form of _Saxifraga granulata_ wherein the petals are replaced by stamens, so that there are fifteen stamens. A similar change has been observed in _Capsella bursa-pastoris_.

Cramer figures and describes a stamen occupying the place of a petal in _Daucus Carota_.[318] Turpin[319] describes a similar occurrence in _Monarda fistulosa_, in which the lower lip terminated in an anther, but this may have been a case of adhesion. Moquin cites from Chamisso, _Digitalis purpurea_, and from Jussieu, _Asphodelus ramosus_, as having presented this change, and Wiegmann[320] has seen anthers developed on the awns of _Avena chinensis_. In semi-double flowers of _Ophrys aranifera_ and _Orchis mascula_, the lateral petals are occasionally partially antheroid, and others occur in which two of the outer series of stamens, which are ordinarily suppressed, are present, but in a petaloid state. Reichenbach[321] figures an ill.u.s.tration of this change, and also Moggridge.[322]

=Staminody of the pistils.=--The existence of this change has been denied by several authors, nevertheless, it is of sufficiently common occurrence. Alexander Braun notices the transformation of pistils into stamens in Chives (_Allium Scorodoprasum_), and in which three stamens appeared in the place of as many pistils, and had extrorse anthers, while the six normal anthers are introrse. In the horse-radish (_Armoracia rusticana_), two of the carpels are frequently converted into stamens, while two other organs absent from the normal flower make their appearance as carpels. Roeper has observed this phenomenon in _Euphorbia pal.u.s.tris_,[323] and in _Gentiana campestris_.[324] In these examples one of the carpels was apparently absent, and its place supplied by an anther. Roeper has also mentioned a balsam with a supernumerary stamen occupying exactly the position of a carpel.[325]

Agardh has observed a similar thing in a hyacinth, one half of the fruit of which contained seeds, and the other half, anthers. B. Clarke mentions an instance in _Mathiola incana_ in which the carpels were disunited, and antheriferous at the margin.[326]

The pa.s.sage of pistils to stamens in willows has been frequently remarked, as in _Salix babylonica_, _silesiaca_, _cinerea_, _Caprea_ and _nigricans_. One of the most curious ill.u.s.trations of this transformation in this genus is given by Henry and Macquart (Erst.

Jahrb. des bot. Vereines am m. et n. Rhein., 1837). In the flowers in question the series of changes were as follows:--first, the ovary opened by a slit, and then expanded into a cup; next, anther-cells were developed on the margin of the cup, with stigmas alternating with them, the ovules at the same time disappearing; lastly, the margin became divided, and bore three perfect anthers, which in the more perfect states were raised on three filaments.

_Campanula persicifolia_, _C. rapunculoides_, and _C. glomerata_ have been observed to present an anther surmounting the pistil.[327] Double tulips often present this change, and a like appearance has been observed in _Galanthus nivalis_, and _Narcissus Tazetta_.

Moquin mentions the existence of this condition in a female plant of maize, some of the pistils of which were wholly or partially converted into anther-like organs. Mohl has recorded an a.n.a.logous malformation in _Chamaerops humilis_, and in which the three carpels were normally formed, and only differed from natural ovaries in this, that along the two edges of the ventral suture there was a yellow thickening, which a cross section of the ovary showed to be an anther-lobe filled with pollen.[328]

In _Tofieldia calyculata_ a similar subst.i.tution of a stamen for a carpel has been observed by Klotsch,[329] and Weber[330] gives other instances in _Prunus_ and _Paeonia_. Corresponding alterations may be met with in cultivated tulips, in the cowslip and other plants. In most of the above cases the trans.m.u.tation has been perfect, but in quite an equal number of cases a portion only of the carpel is thus changed, generally the style or the stigma; thus Baillon describes the stigmas of _Ricinus communis_ as having been in one instance antheriferous.[331]

Moggridge figures a flower of _Ophrys insectifera_ in which the rostellate process was replaced by an anther.[332]

Mohl remarks that the change of pistils into stamens is more common in monocarpellary pistils than it is in those which are made up of several carpels. It seems clear that in this transformation the lobes of the anther and the development of pollen have no relation to the production of ovules.