FLORA HONGKONGENSIS
Class I. DICOTYLEDONS.
Stem, when perennial, consisting of a pith in the centre, of one or more concentric circles containing fibrons tissue, and of the bark on the outside. Seeds with two cotyledons, the young stem in germination proceeding from between the two lobes of the embryo or from a notch at its summit.
The above characters are all that can be said to be constant to separate Dicotyledons from Monocotyledons ; these two great classes have, however, each a peculiar habit which in most cases is readily recognized. All Hongkong trees or shrubs, except Palms and Bamboos, are Dicotyledons, so also are all plants with opposite or whorled or netted-veined leaves (except Smilax and some Aroidecs), and almost all those which have the parts of the flowers in fours, fives, or eights. (The following list of Orders is intended to show the arrangement adopted in this work. The characters given are not absolute, nor without exception, and are inserted only for the purpose of calling the attention to one or two of the most striking or most important features of each Order. In some cases where an Order is only represented in the island by some ano- malous genus, its exceptional character is placed in a parenthesis.) Subclass I. Thalamiilorse. — Petals distinct from the calyx and from each other, sel- dom wanting. Stamens hypogynous. § 1. Ovary apocarpous. I. Ranunculace.^:. Sepals petal-like, 5 or fewer. Stamens indefinite. No arillus. Herbs with alternate leaves ; or climbers with opposite leaves. II. DiLLENiACE.E. Sepals herbaccous, 5 or fewer. Stamens indefinite. Seeds with arillus. Woody. Leaves alternate. III. Magnoliaceji;. Sepals and petals forming 3 or more series, and imbricate in each series. Carpels indefinite. Trees or climbers. IV. /iNONACEiE. Sepals 3, valvate. Petals 6, in 2 scries, valvate or slightly imbricate in each series. Carpels indefinite. Stem woody. V. Menispermace.e. Flowers small, unisexual. Sepals in 1 or 2 series. Petals in 2 series. Stamens definite, opposite the petals. Carpels 3 or 1, uniovulate. Climbers. VI. Berberide.e. Characters nearly of Memspermacece, but several ovules in each car- pel. (Climber, with digitate leaves.) §2. Ovary syncarpo'is. Placentas parietal. VII. Papaverace.e. Sepals 2. Petals 4. Stamens indefinite. Albumen copious. Herbaceous. VIIT. Crucifeb.e. Sepals 4. Petals 4. Stamens 0, of which 4 longer. ITcrbaecous.
