54 SHADE-TREES IN TOWNS AND CITIES 



their other neighbors of the forest. It is the flower of a 

 plant that largely determines its position in botanical classi- 

 fication. 



The gingko, although differing from the pines in many 

 other ways, is like them in its mode of flowering. The 

 staminate and the pistillate flowers are borne on different 

 branches of the same tree. The female flowers consist of 

 two naked ovules which receive the pollen. These ripen 

 into the fruit of the gingko, which is a fleshy drupe resem- 

 bling a small plum. The drupes are ill-scented, and are con- 

 sidered by some as an objection to the tree. Gingkos, how- 

 ever, do not fruit until they are about thirty or forty years 

 old, and the fruiting season does not last very long. 



Sweet Gum {Liquidambar styraciflua Linn.). In bril- 

 liancy of autumn foliage few trees surpass the liquidam- 

 bar, or sweet gum. The color of its beautiful star-shaped 

 leaves varies from deep red to yellow, and, in addition, some 

 leaves are dark purple and brown. It grows perfectly 

 straight and forms a symmetrical top. Like the magnolias, 

 however, it has succulent roots, and is somewhat difficult to 

 transplant. Naturally, the sweet gum is usually found in 

 wet, rich soil bordering streams or swamps. The average 

 street is too dry for them. When under favorable condi- 

 tions the trees once become established they are extremely 

 beautiful and more than offset the extra care that is required 

 in transplanting and the litter caused by their fruit. 



THE CATALPAS 



Hardy Catalpa (Catalpa Catalpa (Linn.) Karst.). The 

 catalpa is an ornamental tree. It has very large leaves and 

 in June is resplendent with pyramid-shaped clusters of 

 flowers resembling those of the horse-chestnut. It naturally 



