In Orchidaceæ entire absence of the labellum, frequently without any other perceptible change, is of common occurrence. The writer has seen numerous specimens of the kind in Ophrys apifera and O. aranifera; also in Dendrobium nobile, Ærides odoratum, Cypripedium villosum, Listera ovata, &c. Morren[467] mentions analogous deficiencies in Zygopetalum maxillare, Calanthe sp., and Cattleya Forbesii. In most of these there was also a fusion of the two lower sepals, which were so twisted out of place as to occupy the situation usually held by the labellum. At the same time the column was partially atrophied. To this deficiency of the lip the author just quoted proposed to apply the term acheilary, α-χειλαριον. Mr. Moggridge has communicated to the author an account of certain flowers of Ophrys aranifera, in which the petals were deficient, sometimes completely, at other times one or two only were present.
Meiophylly of the andrœcium.—Suppression of one or more stamens, independently of like defects in other whorls, is not uncommon, even as a normal occurrence, e.g. in Carlemannia, where the flower, though regular, has only two stamens, and other similar deficiencies are common in Dilleniads.
Seringe relates the occurrence of suppression of some of the stamens in Diplotaxis tenuifolia,[468] St. Hilaire in Cardamine hirsuta, others in C. sylvatica.
In Caryophyllaceæ suppression of one or more stamens has been observed in Mollugo cerviana, Arenaria tetraquetra, Cerastium, &c.[469] Among violets the writer has observed numerous flowers in which two or three stamens were suppressed. Chatin[470] alludes to a similar reduction in Tropæolum, while in flowers that are usually didynamous absence of two or more of the stamens is not unfrequent, e.g. in Antirrhinum, Digitalis, while in a flower of Catalpa a solitary perfect stamen, and a complete absence of the sterile ones usually present, have been observed. This might have been anticipated from the frequent deficiencies in the staminal whorl in these plants under what are considered to be normal conditions. Reduction of the staminal whorl is also not unfrequent in Trifolium repens and T. hybridum, and has been seen in Delphinium, &c.[471]
Meiophylly of the gynœcium.—Numerical inequality in the case of the pistil, as compared with the other whorls of the flower, is of such common occurrence, under ordinary circumstances, that in some text-books it is looked on as the normal condition, and a flower which is isomerous in the outer whorls is by some writers not considered numerically irregular if the number of the carpels does not coincide with that of the other organs.
But in this place it is only necessary to allude to deviations from the number of carpels that are ordinarily found in the particular species under observation. As illustrations the following may be cited:—Arenaria tetraqueta, which has normally three styles, and a six-valved capsule, has been seen with two styles, and a four or five-valved capsule. Moquin relates an instance in Polygala vulgaris where there was but a single carpel, a condition analogous to that which occurs normally in the allied genus Mozinna. Reseda luteola occasionally occurs with two carpels only, while Aconites, Delphiniums, Nigellas, and Pæonies frequently experience a like diminution in their pistil.
In a flower of Papaver Rhæas the writer has recently met with an ovary with four stigmas and four parietal placentæ only, and to Mr. Worthington Smith he is indebted for sketches of crocus blooms with two, and in one instance only a solitary carpel.
Moquin cites the fruit of a wild bramble (Rubus) in which all the little drupes which go to make up the ordinary fruit were absent, except one, which thus resembled a small cherry. In Cratægus the pistil is similarly reduced to a single carpel, as in C. monogyna.
The writer has on more than one occasion met with walnuts (Juglans) with a single valve and a single suture.[472] If the ovary of Juglans normally consisted of two valvate carpels, the instances just alluded to might possibly be explained by the suppression of one carpel, but the ovary in Juglans is at first one-celled according to M. Casimir de Candolle.