Fig. 415.—Capparis spinosa.
Order 4. Capparidaceæ (Capers). The relationship with the Cruciferæ is so close that certain forms are with difficulty distinguished from them. The diagram of the flower is the same in the number and position of its parts, but it differs in the modifications which occur in the development of the stamens. In some genera all 4 stamens are undivided; in others both the 2 median ones are divided as in the Cruciferæ (6 stamens, but not tetradynamous) (Fig. [414]); in other genera only 1 of these; in other instances again they are divided into more than 2; and finally the 2 lateral ones also may be found divided, so that indefinite stamens occur (Fig. [415]). The bicarpellate gynœceum is unilocular (without replum), but more than 2 carpels may occur. The ovary is elevated on a stalk (sometimes as much as 1 foot in length); also between the stamens and corolla a similar stalk may be found (Fig. [414]). The fruit is long and siliquose (Cleome, Polanisia, Gynandropsis), or a berry (Capparis). Endosperm absent. Some have zygomorphic flowers. Gamosepalous calyx and perigynous flowers also occur.—350 species; especially in the Tropics. The majority are trees and shrubs, and they differ also from the Cruciferæ in having distinct stipules present in some species.
“Capers” are the flower buds of the climbing, thorny shrub, Capparis spinosa (Fig. [415]), which grows in the Mediterranean.
Family 11. Cistifloræ.
The flowers in this family are perfect, regular (except Resedaceæ, Violaceæ), hypogynous, the perianth-leaves free (a few have them slightly united), æstivation most frequently imbricate; they are eucyclic in the andrœcium, and most frequently in the other parts, and generally 5-merous with S5, P5, A5 + 5, G3, but other numbers also occur; several have indefinite stamens, but the stamens arise (where the development is known) in centrifugal order and are arranged, often very distinctly, in bundles; in other words, the large number of stamens is formed by the splitting of a small number (most frequently 5); a true spiral arrangement is never found. Gynœceum syncarpous, multicarpellary (Dilleniaceæ and a few Resedaceæ are apocarpous), most frequently the number of carpels is 3, forming a unilocular ovary with parietal placentæ, but parallel with this, multilocular ovaries, with the ovules placed in the inner angle of the loculi, are also found, and a few genera have a free, centrally-placed placenta. The fruit is most frequently a capsule. The dehiscence is never with a “replum,” i.e. the persistent frame of the placenta, as in the family Rhœadinæ. One half of the orders has endosperm (Violaceæ, Cistaceæ, Droseraceæ, Bixaceæ, Ternstrœmiaceæ, etc.), the other has no endosperm (Resedaceæ, Hypericaceæ, Elatinaceæ, Tamaricaceæ, etc.); some have a curved, the majority a straight embryo. The family is scarcely quite natural; in the future the orders will probably be arranged differently.
Order 1. Resedaceæ (Mignonettes).—Herbs or small shrubs with spirally-placed leaves and very small, gland-like stipules (as in Cruciferæ); the ☿, hypogynous flowers are zygomorphic, and arranged in racemes or spikes typically without bracteoles. The zygomorphic structure is produced by the greater development of the posterior side of the flower, especially the petals and the nectary (“disc,” in Fig. [416] d) which is situated between the petals and stamens; in general there are 5–8 free sepals and petals, the latter consisting of a large scale-like sheath with a fimbriated blade (see Fig. [416]); stamens numerous; carpels 6–2 united together; ovary unilocular with parietal placentæ, but the cavity of the ovary is not closed at the top. In Astrocarpus the gynœceum is apocarpous. The fruit is most frequently a capsule; the seeds are reniform, without endosperm, and the embryo is curved.
This order connects the Rhœadinæ with the Cistifloræ. It is closely allied to the Rhœadinæ by its external appearance, even by the smell and taste, the parietal placentation, structure of the seeds, the inflorescences, etc., whilst by the irregular flowers and the disc placed at the posterior side of the flower, it is allied to Capparidaceæ, but differs from this order in not having its characteristic number (2–4) and by the very different mode of dehiscence of the fruit, etc. It differs from the other orders of this family chiefly in the fact that the number of the perianth-leaves is not constantly 5. In Reseda luteola both the calyx and corolla appear to be 4-leaved, because the posterior sepal is suppressed, and the 2 posterior petals are united. Where there are 10 stamens, they stand in 2 whorls, i.e. in front of the sepals and petals; if there are several, their position depends upon the splitting.—Astrocarpus is remarkable for its apocarpous fruit and the position of the ovules on the dorsal suture of the carpel.
The yellow, flat disc at the back of the flower serves as a nectary, the honey being protected by the lobes of the petals. If pollination by insects is not effected, then self-pollination may take place, at all events in R. odorata.
45 species; the majority in the Mediterranean and in Persia. Reseda odorata (from Egypt) is cultivated on account of its sweet scent; R. luteola (“Dyer’s Weed”) yields a yellow dye.
