1570. They have rudiments of roots and a stem, together with foliage, because they are the prototypes of these three organs.
1571. The ring of their capsules corresponds to the midrib of the leaf. In the preceding order the capsule was only an upsprung stalk; but it is here an upsprung and unfolded leaf, the prototype of the bud-development.
1572. The fern-capsules, namely, the true seeds, are an accumulation of leaf-buds at the extremity of the fascicle of spiral vessels. The indusium is the upraised epidermis, which opens in a spathose manner; it consequently stands in the signification perhaps of the floral spathe or involucrum. They correspond to the Fuci.
1573. Fourth order. Floral ferns—Fluviales. If the tracheal plants be exalted unto the flower, male organs cannot fail in at once beginning to develop. I place therefore in this order the Naiadaceæ with very arrested blossoms, and simply stamina without calyx and corolla. The spiral vessels are rather doubtful.
1574. Fifth order. Fruit ferns—Coniferæ. Tree with imperfectly-formed spiral vessels, stamina without corollæ, seeds without ovarium; thus agreeing with the Cryptogamia even to the stamina; they form likewise sixteen families. (Vid. Tab. B.)
SEXUAL PLANTS.
1575. So soon as the three tissues separate completely from each other into bark, liber, and wood, while the tracheæ are arranged circularly into several clusters or groups, does the antagonism of these organs also make its appearance, and exhibit itself as sex in the floral organs.
1576. This separation can only be attained through the influence of the air and light, whereby the sexual organs are conditionated. These plants have therefore the several organs of the trunk and blossom.
1577. Anthers can be wanting to none of the following plants. Now, the anthers are leaf-buds; the leaf-formation must be therefore developed also in their antagonism, or in the seed. The leaves of the seed, however, are called seed-lobes; consequently all seeds of sexual plants have seed-lobes or cotyledons.
1578. Now the perfect seed is the whole plant in miniature with root, stalk, and leaf. This formation is, however, only possible where there is a sex, or where the vegetable tissues have emerged self-substantially from each other.