2. Planera. Flowers appearing with the leaves. Ovule one. Fruit wingless, nut-like.
Tribe II. CELTIDEÆ. As in Tribe I., but the diœcious-polygamous flowers upon branches of the same year; anthers introrse; fruit a drupe; embryo curved.
3. Celtis. Ovary 1-ovuled. Flowers appearing with the leaves. Leaves 3-nerved at base.
Tribe III. CANNABINEÆ. Flowers diœcious; the sterile racemed or panicled; the fertile in clusters or catkins, the calyx of one sepal embracing the ovary. Filaments short, erect in the bud. Stigmas 2, elongated. Ovary 1-celled, with a pendulous ovule, forming a small glandular achene in fruit. Embryo curved or coiled.—Erect or climbing herbs, with watery juice, mostly opposite lobed or divided leaves, persistent stipules, and a fibrous inner bark.
4. Cannabis. Fertile flowers spiked-clustered. Leaves 5–7-divided. Erect.
5. Humulus. Fertile flowers in a short spike forming a membranaceous catkin in fruit. Leaves 3–5-lobed. Climbing.
Tribe IV. MOREÆ. Flowers unisexual, racemose, spicate or capitate; calyx becoming fleshy or juicy in fruit. Anthers inflexed in the bud. Style undivided or 2-parted, filiform; ovule pendulous; fruit an achene, embryo curved.—Trees or shrubs, with milky juice, alternate leaves, and fugacious stipules.
6. Maclura. Sterile flowers in loose racemes; fertile in globose heads. Leaves entire.
7. Morus. Fertile and sterile flowers in separate spikes. Leaves dentate, 3-nerved.
Tribe V. URTICEÆ. Flowers unisexual. Filaments indexed in the bud. Style or stigma simple. Ovary 1-celled, with an erect ovule, forming an achene in fruit. Embryo straight.—Herbs with watery juice, tough fibrous bark, and opposite or alternate leaves; often armed with stinging hairs.