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THE KINDS OF PLANTS 



families. More than 100 genera and 1500 species. Bepresentatives 

 are elm, hackberry, mulberry, osage orange, nettle, hop, hemp. 



a. Trees. 



b. Fruit a samara 1. JJlmus 



bb. Fruit a small drupe 2. Celt is 



bbb. Fruit as large as an orange, formed of the whole mass of 



the pistillate flower-cluster 3. Toxylon 



bbbb. Fruit resembling a blackberry, formed of the pistillate 



flower-cluster 4. 3foms 



aa. Herbs. 



b. Leaves digitately lobed or divided. 



c. Plant standing erect 5. Cannabis 



cc. Plant twining 6. Hamulus 



bb. Leaves not lobed : plant with stinging hairs 7. Urtica 



1. tTLMUS. Elm. 



Trees, mostly large and valuable for timber, with rough-furrowed bark : 

 leaves alternate (2-ranked), ovate and straight-veined, dentate: flowers small 

 and not showy, appearing in earliest spring, sometimes diclinous, the calyx 

 4-9-parted, the anthers 4-9 on long filaments: ovary generally 2-loculed, 

 ripening into a 1-seeded wing-fruit. 



a. Leaves large, rough on the upper surface : fruit large, nearly orbicular. 



U. fiilva, Michx. Slippery elm. Fig. 448. Middle-sized or small tree 



with inner bark mucilaginous or "slippery " in spring : leaves 6-8 in. long 



and half or more as broad, ovate elliptic and unequal-sided, doubly serrate, 



448. rimusfulva. 



449. Uhmis Americana. 



450. Ulmus raceinosa. 



very rough above and softer beneath: samara %-% in. long, orbicular or 

 nearly so, with the seed in the center: flowers in dense clusters. Common. 



aa. Leaves not very rough above: fruit oral, deeply notched at the apex. 



U. Americana, Linn. Common or white elm. Figs. 91-95, 146, 449. Talland 

 graceful tree: leaves elliptic-oval, serrate: samara small, more or less hairy 

 on the thin wing, the notch in the apex extending nearly to the seed : flowers 

 hanging on slender stalks. One of the finest of American trees. 



