fiEVlEW ON SEED DISPERSAL 



163 



for food, but if they are not eaten they may grow. The seeds of 

 nnnv yilants aie blown on the snow. The old stalks of weeds, stand- 

 ing through the winter, may serve to disseminate the 

 plant. Seeds are carried by water down the streams 

 and along shores. About woollen mills strange plants 

 often spring up from seed brought in the fleeces. 

 Sometimes the entire plant is rolled for miles before 

 the winds. Such plants are "tumble-weeds." Exam- 

 are Eussian thistle (Fig. 99), hair-grass or 

 tumble-grass (Panieum capillare), cyclone plant (Cy- 

 clolomaplatyphyllum), and white amai'anth 

 (Amaranthus albus). About seaports 

 strange plants are often found, having been 

 JM sti. ilui^ I luk-. introduced in the earth that is used in sliips 



for ballast. These plants are usuallv known as "ballast plants." Most 

 of them do not persist long. 



A ziiK' lined box may be fitted to the school-room window and used 

 us a receptacle for plants. A faucet under one corner will drain off the 

 accmnnlated water. Geranium, coleus, grevillea, some begonias, and 

 other plants may be grown in the conditions which are present in most 

 schoolrooms. If the plants become sick, take them to the florist's 



