CHAPTER XXX 

 DICOTYLEDONOUS PLANTS 



The characters of this great division have already been given 

 (page 304). It includes 100,000 or more species and therefore 

 we can do little more than mention a few of the most important. 



Salicace.i-: (Willow Family). — Trees or shrubs; leaves al- 

 ternate and stipiilate ; both kinds of flowers in catkins ; stamens 

 one to five, or more ; pistil one-chambered and two- to four- 

 valved ; fruit a dry eapsnle containing numerous seeds, each 

 furnished with a silky down. Wood soft and light Only two 

 genera but taany species. ' 



The genus f<(iJix contains the many speciesof the willows and 

 the genus Pojnihis contains the poplars and cottonwoods. 



JuGLAXDACE-E (Waluut Family). — Trees- leaves alternate, 

 pinnately compound and without stipules; inflorescence, stami- 

 nate flowers in catkins, pistillate flowers axillary ; stamens three 

 to forty inserted on base of bract ; ovary two- to four-chambered ; 

 styles two; fruit a drupaceous nut. A small family restricted 

 to temperate climates. 



The American black walnut (Julians nigra) and white wal- 

 nut or butternut (./. cinerea) are well-known trees which are 

 prized for their nuts ; the former is one of the most valuable of 

 our American woods. The so-called English walnut (J. regia) 

 is in reality a Persian walniit which is grown extensively in Cali- 

 fornia for its nuts and for its wood. 



The American hickories {Hicoria or Carya), of which there 

 are many species, are well-known trees which are valued both for 

 their wood and nuts. The pecan (H. olivceformis) is grown for 

 its nuts, which are of vei^- great commercial value (Fig. 167). 



Betulace.e. — Trees or shrubs ; simple, alternate leaves with 

 decidiious stipules; staminate flowers in catkins; pistillate 



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