348 THE KINDS OF PLANTS 



M. alba, Linn. White mulberry. Fig. 511. Leaves light green and 

 usually glossy above, the veins prominent and whitish beneath, the teeth 

 usually rounded or obtuse: fruit of variable size, often 1^ in. long, whitish, 

 violet, or purple. China; planted for ornament and for its fruit, also for 

 feeding silkworms. The much-planted Russian mulberry is a form of it. 



5. CANNABIS. HEMP. 



Tall, strong, dioecious herbs with 5-7 leaflets: fertile flowers in clus- 

 ters, with 1 sepal surrounding the ovary, and 2 long, hairy stigmas: sterile 

 flowers in racemes or panicles, with 5 sepals and 5 drooping stamens. 



C. sativa, Linn. Hemp. Six to 10 ft., strong-smelling, blooming all 

 summer: leaflets lanceolate, large toothed. Old World; cultivated for fiber 

 and sometimes escaped in waste places. 



6. HtTMULUS. HOP. 



Twining dioecious herbs of tall growth, with 5 sepals in the sterile 

 flowers, the stamens erect: fertile flowers with 1 sepal, 

 2 flowers under each scale of a short, thin catkin which 

 becomes a kind of cone or "hop." 



H. Lupulus, Linn. Common hop. Perennial, rough- 

 hairy: leaves broad-ovate, deeply 3-lobed (only rarely 

 5 7-lobed): sterile flowers in panicles 26 in. long: pis- 

 tillate catkin enlarging into a "hop" often 2 in. or 

 more long. A native plant, cultivated for hops and 

 sometimes for ornament. 



H. japonicus, Sieb. & Zucc. Japanese hop. Fig. 

 511. Morus alba. 179. Annual: leaves not less than 5-lobed: fertile 

 catkin not enlarging into a hop. Japan; much 

 cultivated for ornament. 



7. tJRTICA. NETTLE. 



Erect herbs with opposite simple leaves and stinging hairs, and monoe- 

 cious or dioecious flowers in racemes or dense clusters, the calyx of 4 

 separate sepals: stamens 4: stigma sessile: fruit an ovate flat achene. The 

 following are perennials with flowers in panicled spikes: 



U. gracilis, Ait. Common nettle. Two to 6 ft.: leaves ovate-lanceolate, 

 serrate, on long petioles. Common in low grounds. 



II. dioica, Linn. Not so tall: leaves ovate-cordate and deeply serrate, on 

 rather short petioles, downy underneath. Weed from Europe, very stinging. 



XI. ARISTOLOCHIACE^E. 

 BIRTHWORT FAMILY. DUTCHMAN'S PIPE FAMILY. 



Low acaulescent herbs, or tall twining vines: leaves basal or alter- 

 nate, without stipules, petiolate, roundish or kidney-shaped: flowers 

 regular or irregular, perfect: perianth-tube brown or dull, valvate in 



