264, Flower of Saururus (lizard-tail); achlamydeous. 265, Flower of Fraxinus (ash). 266, Flower of Salix (willow,) staminate. 267, pistillate.
421. Imperfect flowers are also of frequent occurrence. They are deficient in respect to the essential organs. A sterile or staminate flower (denoted thus ♂) has stamens without pistils. A fertile or pistillate flower (♀) has pistils without stamens. Such flowers being counterparts of each other, and both necessary to the perfection of the seed, must exist either together upon the same plant or upon separate plants of the same species. In the former case the species is monoecious (8 ) as in oak; in the latter case dioecious (♂ ♀ ) as in willow. The term diclinous, denoting either 8 or ♂ ♀ without distinction, is in common use.
268, Pistillate flower of Balm-of-Gilead. 269, Staminate. 270, Diploclinium Evansianum.
a, staminate; b, pistillate.
422. A neutral flower is a perianth or calyx only, having neither stamens nor pistils. Such are the ray-flowers of many of the Composite, and of the cymes of Hydrangea, high cranberry, etc., which in cultivation may all become neutral, as in the snow-ball.
423. Unsymmetrical flowers. The term symmetry, as used in botany, refers to number only. A flower becomes unsymmetrical by the partial development of any set or circle in respect to the number of its organs. The mustard family affords a good example.
424. Flowers of the cruci-fers. The flowers of mustard, cress, etc, are understood to bo 4-merous (4V) The sepals are four, petals four, but the stamens are six and the styles but two. The stamens are arranged in two circles, having two of those in the outer circle suppressed or reduced to mere glands. Two of the carpels are also suppressed. (256.)
425. In the mint family and the figworts one or three of the stamens is generally abortive. Here, while the flowers are 5V, the stamens are four in some species and only two in others. The missing stamens, however, often appear in the guise of slender processes - the rudiments of stamens - proving in an interesting manner the natural tendency to symmetry.
426. Other- examples. In the V flowers of poppy, the sepais are but two; in 5V spring-beauty they are but two; in both cases too few for symmetry, In larkspur the 5V flowers have but four petals, and in monk's-hood, also 5V, the petals are apparently but two strangely deformed bodies. A careful inspection, however, generally reveals the other three, very minute, in their proper places, as displayed in the cut. (283.)
271, '• Radiant" panicle of Hydrangea quercifolium; the larger flowers neutral.
427. "Organs opposite" is a condition much less frequent than "organs alternate," but is highly interesting, as being sometimes characteristic of whole families. Thus in the primrose, thrift, and buckthorn families, the stamens always stand opposite to the petals!
428. How happens this? Among the primworts this question is solved in the flowers of Lysimachia and Samolus, where we find a circle of five teeth (abortive filaments) between the petals and stamens, alternating with both sets, thus restoring the lost symmetry. Hence we infer that in such cases generally a circle of alternating organs has been either partially or wholly suppressed. In the buckthorn, however, a different explanation has been given.
Diagrams. 272, Flower of Samolus, showing the rudimentary stamens alternating with the perfect. 273, Flower of a Labiate plant, showing the place of the deficient stamen. 274, Flower of Asarum; three sepals, twelve stamens, etc. 275, Flower of Saxifrage; two pistils, ten stamens, etc.
429. The multiplication of organs is exceedingly common, and usually according to a definite plan. The increase takes place, as a rule, by circles, and consequently by multiples. That is, e. g., the stamens of a 3V flower, if increased, will be so by 3s; of a 5V flower by 5s, etc., sometimes to the extent of twenty such circles.
430. Crowfoots and roseworts. In the crowfoot family the stamens are almost always multiplied. The carpels are also generally multiplied, yet often, on the contrary, diminished, as in the paeony. In Rosacea?, also, the stamens are generally multiplied, while the carpels exist in all conditions as to number. Thus in strawberry they are multiplied, in the apple they are regularly five, in agrimony reduced to two, and in the cherry to one.
431. Other cases. In Magnolia the 3v flowers have three sepals in one circle, six or nine petals in two or three circles, numerous stamens and carpels in many circles of each. In the 4V flowers or blood-root there are two sepals, eight petals, twenty-four stamens, and two carpels.
432. Increment by clusters (chorisis). In other cases the organs seem to bo increased in number by clusters rather than by circles, as when in the same circle several stamens stand in the place of one, e. g., in squirrel-corn, st. johnswort, linden. Such cases afford wide scope for conjecture. Perhaps each cluster originates by division, as the compound from the simple leaf; or as a tuft of axillary leaves; or thirdly, by a partial union of organs.
433. Appendicular organs (§ 407) consist of spurs, scales, crown, glands, etc., and often afford excellent distinctive marks. The old term nectary was indiscriminately applied to all such organs, because some of them produced honey.