=Meiophylly of the flower as a whole.=--In the preceding sections a reduction in the parts of each individual whorl has been considered without reference to similar diminution in neighbouring verticils. It more commonly happens, nevertheless, that a defect in one series is attended by a corresponding imperfection in adjoining ones. Thus trimerous fuchsias and tetramerous jasmines may frequently be met with, and Turpin describes a tetramerous flower of _Cobaea scandens_. Perhaps monocotyledonous plants are more subject to this numerical reduction of the parts of several verticils than are other flowering plants. Thus, in both _Lilium lancifolium_ and _L. auratum_ the writer has frequently met with pentamerous flowers. In _Convallaria maialis_ a like deviation not unfrequently occurs.[474] M. Delavaud has recorded a similar occurrence in a tulip.[475]

Dimerous crocuses may also sometimes be met with. In one flower of this nature the segments of the perianth were arranged in decussating pairs, and the four stamens were united by their filaments so as to form two pairs.

M. Fournier mentions something of the same kind in the flower of an _Iris_.[476]

Orchids seem peculiarly liable to the decrease in the number of their floral organs. Prillieux[477] mentions a flower of _Cattleya amethystina_ wherein each whorl of the perianth consisted of two opposite segments.

The same observer has put on record instances of a similar kind in _Epidendrum Stamfordianum_. In one flower of the last-named species the perianth consisted of one sepal only, and one lip-like petal placed opposite to it.[478] Morren[479] describes a flower of _Cypripedium insigne_, in which there were two sepals and two petals. Of a similar character was the flower found by Mr. J. A. Paine, and described in the following terms by Professor Asa Gray in the 'American Journal of Science,' July, 1866:--"The plant" (_Cypripedium candidum_) "bears two flowers: the axillary one is normal; the terminal one exhibits the following peculiarities. The lower part of the bract forms a sheath which encloses the ovary. The labellum is wanting; and there are two sterile stamens, the supernumerary one being opposite the other, _i.e._ on the side of the style where the labellum belongs. Accordingly the first impression would be that the labellum is here transformed into a sterile stamen. The latter, however, agrees with the normal sterile stamen in its insertion as well as in shape, being equally adnate to the base of the style. Moreover, the anteposed sepal is exactly like the other, has a good midrib and an entire point. As the two sterile stamens are anteposed to the two sepals, so are the two fertile stamens to the two petals, and the latter are adnate to the style a little higher than the former. The style is longer than usual, is straight and erect; the broad, disciform stigma therefore faces upwards; it is oval and symmetrical, and a light groove across its middle shows it to be dimerous. The placentae, accordingly, are only two. The groove on the stigma and the placentae are in line with the fertile stamens.

Here, therefore, is a symmetrical and complete, regular, but dimerous orchideous flower, the first verticil of stamens not antheriferous, the second antheriferous, the carpels alternate with these; and here we have clear (and perhaps the first direct) demonstration that the orchideous type of flower has two stamineal verticils, as Brown always insisted."

[Ill.u.s.tration: FIG. 198.--Regular dimerous flower of _Calanthe vest.i.ta_.]

[Ill.u.s.tration: FIG. 199.--Regular dimerous flower of _Odontoglossum Alexandrae_.]

Dr. Moore, of Glasnevin, kindly forwarded to the writer a flower of _Calanthe vest.i.ta_ (fig. 198), in which there were two sepals only, anterior and posterior, and two petals at right angles to the two sepals. The lip was entirely wanting, but the column and ovary were in their usual condition. In _Odontoglossum Alexandrae_ a similar reduction of parts has been observed by the author (fig. 199).

It is curious to observe in these flowers how precisely one sepal occupies the position of the labellum, and how the lateral petals are displaced from the position they usually occupy, so as to form a regular flower, the segments of which decussate, thus giving rise to a species of regular peloria.

The genus _Maelenia_ was established on a malformed flower of _Orchis_ of similar character to those above mentioned.

=Meiotaxy of the calyx.=--As already mentioned, this term is here employed to denote those ill.u.s.trations in which entire whorls are suppressed. Complete deficiency of the calyx in a dichlamydeous flower seems seldom or ever to occur; the nearest approach to it would be in those cases where the calyx is, as it is termed, "obsolete," but here it is chiefly the limb of the calyx which is atrophied, the lower portion being more or less adherent to the ovary. In what are termed monochlamydeous flowers both calyx and corolla are wanting, as in _Salicineae_ and many other orders.

=Meiotaxy of the corolla.=--Deficiency of the entire corolla occurs in conjunction with similar reductions in other organs, or as an isolated phenomenon in the many apetalous varieties of plants recorded in books.

Deficiency of the corolla was observed in _Campanula perfoliata_ and _Ruellia clandestina_ by Linne, who calls such blooms _flores mutilati_.[480] Drs. Hooker and Thomson relate a similar occurrence in _Campanula canescens_ and _C. colorata_. Some plants seem as a normal occurrence to produce flowers of different construction, and are hence termed dimorphic, as in many _Malpighiaceae_, _Violaceae_, _Oxalidaceae_, in some of the flowers of which the petals are altogether wanting, while in others the corolla is developed as usual. This deficiency of the corolla is frequently, but not invariably, a.s.sociated with an increased fertility. Thus, in some violets the flowers produced in summer, and in which the petals are either entirely suppressed or are more or less atrophied, are always fertile, while the blossoms developed in spring, and in which the petals are always present, are much less fertile. In _Oxalis Acetosella_ there are two forms of flower, the one with, the other without, petals, but both seem equally fertile. Linne remarks that many plants which, in warm lat.i.tudes, produce a corolla, do not do so when grown in colder climates. Thus, certain species of _Helianthemum_ are apetalous in Lapland. In the Pyrenees, according to Bentham, the flowers of _Ajuga iva_ are constantly deprived of their corolla.[481]

Apetalous flowers have been noted most frequently in the following plants:

Aconitum, sp. pl.!

Cardamine impatiens.

Cheiranthus Cheiri!

Viola odorata!

Cerastium vulgatum!

Alsine media.

Stellaria.

Lychnis dioica!

Dianthus barbatus, and other Caryophylleae.

Helianthemum, sp.!

Oxalis Acetosella.

Balsamineae.

Malpighiaceae.

Rosa centifolia.

arvensis!

Crataegus!

Medicago lupulina.

Melilotus officinalis.

Ononis minutissima.

Saxifraga longifolia.

Verbasc.u.m Thapsus.

Ajuga iva.

Teucrium Botrys.

Lamium purpureum!

amplexicaule.

Polemonium caeruleum.

Campanula, sp. pl.!

Ruellia clandestina.

Lonicera Periclymenum!

Tradescantia, sp.!

Hymenocallis.

The following references apply some to apetalous and others to dimorphic flowers, but it must be remembered that the latter plants are not necessarily wanting in petals or stamens, &c., though the functional activity of the parts may be impaired:

A. de Jussien, 'Monogr. Malpigh.,' pp. 82, 334. Torrey, 'Fl.

New York,' i, p. 428. Hooker and Thomson, 'Journ. Linn. Soc.,'

ii, p. 7, Guillemin, 'Archiv. de Botan.,' i, p. 412. Michalet, 'Bull. Soc. Bot. Fr.,' vii. p. 465. Muller, 'Bot. Zeit.,' 1857, p. 729. 'Natural History Review,' July, 1862, p. 235.

=Meiotaxy of the androecium.=--Complete suppression of the stamens occurs normally in the female flowers of unis.e.xual plants, and, as an accidental occurrence, is not very uncommon. _Erica Tetralix_ is one of the plants in which this is said to happen. The variety _anandra_ is said to have been known in France since 1635. Cornuti speaks of it in his 'Enchiridion.' In 1860 M. du Parquet discovered it in peaty woods near Nangis (Seine et Marne).

Many _Umbelliferae_, such as _Trinia vulgaris_, present a like deficiency, while it is of common occurrence among _Rosaceae_ and _Pomaceae_. In the latter group the St. Valery apple, so often referred to, is an ill.u.s.tration. To obtain fruits from this variety it is necessary to apply pollen from another flower, a proceeding made the occasion of festivity and rejoicing by the villagers in some parts of France. In some of the _Artemisias_, especially in _Artemisia Tournefortiana_, all the florets have been noticed to be female, owing to the suppression of the stamens, and this suppression is a.s.sociated with a change in the form of florets.[482] Mr. Moggridge has communicated to the author flowers of _Thymus Serpyllum_ from a plant in which all the stamens were deficient, the flower being otherwise normal.

M. Dupont has given a list of nineteen species of _Chenopodiaceae_ in which female flowers are occasionally produced, owing to the entire suppression of the staminal whorl.[483]

Flowers the subjects either of regular or irregular peloria, _q. v._, are often dest.i.tute of some or all their stamens, _e.g._ _Calceolaria_, _Linaria_, _Viola_, &c., while in cases of synanthy suppression of some of the parts of the flower, and specially of the stamens, is of very common occurrence.

Suppression of the androecium as a teratological occurrence has been most frequently noticed in the following plants, omitting members of those families whose floral construction is normally incomplete in the majority of instances, and exclusive also of cases of subst.i.tution. See also under Heterogamy.

Ranunculus Ficaria!

auricomus!

bulbosus!

Cruciferae, sp. pl.

Violaceae, sp. pl.

Honckenya peploides.

Stellaria.

Caryophyllaceae, sp. pl.

Malpighiaceae, sp. pl.

Tropaeolum majus!

Fragaria vesca!

Rubus, sp.

Pyrus Malus.

Agrimonia vulgaris.

Rosaceae, sp. pl.

Trifolium hybridum.

repens.

Umbelliferae, sp. pl.

Onagraceae, sp. pl.

Hippuris vulgaris.

Callitriche vernalis.

autumnalis.